Hey, guys. I'm about to embark on a project to help a friend figure out why her car is overheating. It's a 1992 Talon 2.0L Non-Turbo. She knows I'm a DSMer (though she doesn't call it that), so she enlisted my help. I took five minutes to look at it, but I didn't get very far into it, yet. I figured I'd post what I know so far and see if someone can give me a little insight as to what to look at. Maybe that'll make it a bit easier on me once I do dive in.

Anyway, the girl called me and told me that someone had told her that the water pump was out. I asked her how sure they were, and she said they were positive. So, I asked her if it was leaking any coolant from anywhere. She said "no". In my experience, a bad water pump leaks because the seal usually goes bad. Could it still be the water pump, even though it's not leaking? I've never seen a water pump just stop circulating. Hell, even when they leak, they usually still circulate, don't they? And the bearing can't be seized up. Since it's run by the timing belt, I'm sure it would've shot that bitch out of there, then I'd be in major trouble.

So, I went to the car and started her up. I only let her idle for five minutes in the driveway. I never took her out on the road. As she sat idling, sure enough, she started to get hot. As the temperature rose, though, I noticed that the cooling fan never kicked on, even though the guage approached the red line. I decided to try and jump that temp switch to see if I could kick that fan on. I know there are a couple of temp sensors on that car. The only one I messed with is the one on the thermostat housing. Is that the right one? Is that the switch that's responsible for cycling that cooling fan off and on? If not, where is it? On the radiator?

Anyway, I disconnected the plug and tried to jump across it to kick the fan on. Nothing happened. I them messed with the circuit breaker for the fan on the fuse block. Took it out, then put it back in. Still nothing. I plugged the temp switch back in and kind of played with the wires a bit, but still was getting no love from it.

Then, as I was going around to the driver's side to make sure I wasn't running it too hot, the fan kicked on all by itself. Seemed a little late to me. I felt like it should've been running much sooner. It had been running for quite a while and hovering near the red before it decided to comply. Not sure if it started because of what I'd done or not. Anyway, I watched the guage, and it dropped to a more reasonable level, but then it decided to start rising again. I decided to kill it before I got it too hot. Then we be really screwed.

So, what do you guys think? I think that there's something wrong with that fan or the switch or the relay. I don't think the pump is bad. If that water wasn't circulating, I don't think the temp would've dropped at all when the fan kicked on. That is, unless the temp sensor for the guage is near that fan, and it was reading the temperature of the coolant near where the fan was cooling it down. But, then if it wasn't circulating, the coolant in the radiator wouldn't be hot at all, right?

I'm a little confused. I'm guessing if it was strictly the fan, it would run much cooler at highway speeds, right? You know, with air passing through the radiator. Let me know what you guys think. As soon as I get a chance, I'm going to dig deeper. I'll post what I figure out.

Thanks for reading this, and I thank you in advance for any advice you might be able to give.

Jon

Take the cap off the water housing tstat hereon the engine and watch the flow. That will tell you if the pump is moving water. Watch the flow as the engine heats up, the flow will increase as the thermostat opens, if it opens late change the thermostat.

If I remember right, there's 4 temp sensors. 2 in the tstat housing, for the A/C and one for the ECM to read. There is another sensor lower for the dash gauge.
Then there's the thermo switch for the fans that's below the left hand side fan (looking from the front)-check that one.

Skim through this thread. It has a lot of overheating advice packed into it.

http://www.dsmcentral.com/invision/index.p...wtopic=3564&hl=

How'd I forget that thread!!

Yes, yes. Learn and laugh at Brett and his painfull battle with his car.

No, it's not. BUT, maybe the alternator/water pump belt is loose enough (and/or the bearing IS seized) that it's not turning the water pump. Kinda far-fetched, but possible, I suppose.

My guess would be the thermostat. If no hot coolant is entering the radiator, the fan will not kick on, right? On the other hand, the guage sensor is on the engine itself, which is rapidly overheating. The temps went down when the fan kicked on because the t-stat finally opened up a little. I'm betting you'll fix your woes with a new t-stat.

Or it could be the canooten valve.

Put a 160* thermostat in it atleast to try. It's only about $6 from Advance Auto Parts. Mine was running funny like that for awhile and the cooler thermostat is finally what kept it below normal operating temp. It stays right at 172* at cruising speeds.

Hey, Germs, the water pump is run by the timing belt. If that bearing was seized up or loose, it would've quit running real quick. I'm sure most of us have gone through the blown timing belt / bent valves fiasco.

My buddy is a mechanic. He said it's rare for a pump to be bad without leaking. He said what usually happens is that corrosion will eat the fins off and the circulation will gradually slow down as the fins get smaller, then stop circulating altogether. The other thing he's seen is for the propeller to just spin off the shaft all together. Then everything's spinning fine, just nothing to push the coolant around.

It's snowing here, so it'll be a few days before I dive in. I'll give her a go probably on Sunday. Got two concerts on Friday and Saturday, so I doubt I'll turn many wrenches on those days. Keep your suggestions coming. I'll let you guys know as soon as I know more.

Jon

The water pump is NOT run off the timing belt on a 2.0 4g63 engine. It is run off an accessory v-belt that is also wrapped around the alternator pulley and the crank pulley.

Well, then this car must not have that engine. There is only one belt on the alternator and crank pulley. I wish that this one weren't run by the timing belt.

Actually, I've never seen a 1g 2-liter where the water pump is run by anything other than the timing belt. Not to argue, or anything. Just never seen it.

Jon

On a 4G63 the timing belt does not drive the water pump.
Not very familiar with the 1.8, or the logistics of its setup. But that may be what your speaking of?

1.8 water pumps run off an accessory belt just like the 2.0

The belts run as follows:

Crank pully-alternator-water pump pully
crank pully-ac compresser
water pump pully-power steering

Timing belt runs the crank, cams, oil pump and a couple idler pullys

That can't be true. If it's a 1g and 2.0L it is a 4G63. Period. And as shown in the picture above, the 4G63 doesn't run the pump off the timing belt. There isn't a difference in the accessory section between turbo and non.

And even if the pump had seized, you would be able to tell by the horrible squeal from under the hood and decreased alternator output.

Then apparently you've never seen a 1g 2.0 before. A 1G 2.0 is a 4g63, period. And a 4g63 does NOT run the water pump from the timing belt, period. The pic that Taxi posted illustrates this pretty clearly.

If you said a 2G non-turbo, I'd be more inclined to believe you because that would be Chryslers 420A and I don't know much about that engine.

I just got off the phone with Mitsubishi. And Jake said the 420a is ran off the timing belt. So Jon you are diving into a 420a.

If its in a 1G, its not a 420A, unless someone did some serious engine/transmission mount fabbing.

That's what I told him and he said that 2G has the 420a. And that it is a Chrysler motor also. He looked them all up and said, the 420a is the only one that is ran off the timing belt.

They way I understand it, the 4g63 is the 2.0L that is made strictly by Mitsubishi and the 420A is the 2.0L made strictly by Chrysler. The 420A is strictly a non-turbo engine from 2g DSMs, though from what I've read, it seems to me that they look the same at first glance. Or, at least I read something about one being a "mirror image" of the other, whatever that means. I'm guessing it means that they're either identical in look and mounting, or that they look the same but one is mounted exactly opposite of the other. Not sure. I'll keep digging.

Apparently, my Talon (the stolen one) is a 4g63. You're right, though, natedogg. I was just remember incorrectly. For that I apologize. I remember that I had to take the belt off the change the pump, but now that I think back, the timing belt doesn't actually run the water pump. It just gets in the way when you have to change it.

As I said before, when I looked at Robyn's car, I didn't dig much. The engine looked the same as mine, so I assume it's also a 4g63. If you check this link, apparently '92 DSMs had both Turbo and Non-Turbo 4g63 engines in them:

http://www.roadraceengineering.com/mitsumo...pplications.htm

Since her engine looks like the same engine as my Talon and I can find nothing about anything other than a 4g63 engine coming out in 1g models, I'm going to assume that her engine is a 4g63 also. Thus, I'm also going to assume that the water pump is the same as mine and I'll have to go through the same process to change it.

This is one thing I found off of the web:

--------------------------------------------------------------------------------
What does 4G63 mean?
What does 420A mean?

These are engine model designators. 4G63 is the Mitsubishi model number for the DSM turbo engine, which was built entirely by Mitsubishi. The 4G63 model number was used for 1G turbo, 1G non-turbo and 2G turbo engines; although the engines are somewhat different from each other, they retain the same basic design.

Please note that there are different 4G63 engines, although posters on the Talon Digest almost invariably mean the turbo 2.0L version. Generally speaking, components from one 4G63 can be fitted to another 4G63, because the basic components (head, block, etc) are the same.

420A is the model of the Chrysler-made 2G 2.0L non-turbo engine. Fundamentally different from the Mitsu 4G63 engines, the 420A represents a distinct shift in DSM evolution, as Chrysler took over engine duties on the non-turbo cars. Generally, components from 420A engines cannot be fitted to the 4G63 engines, or vice versa.
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I'm still learning this stuff, so forgive me if what I wrote above is incorrect.

Jon

I just read this stuff again... man, I feel like an idiot!!!

And, you guys jumped me for it. Good job!! I'm proud of you.

I actually laughed while reading it.

Anyway, let me say again: I was wrong in my recollection!! You guys are right, and I did know that the timing belt doesn't actually run the water pump. It's just that you have to remove the timing belt to get at the pump. I've done the job twice on my own car, it's just that it's been so damned long since I'd done any major mechanical work on a 1g DSM, my memory escaped me.

Sorry guys. I feel like I wasted your time.

I'll try to do better in the future.

Jon

Hey, Goat... now that you mention it, there was a pretty bad squeal when I first started the car. I thought it was the power steering belt, though. When I got to the car, the belt was off. I put it back on and tightened it, though I only used my hands to tighten the belt.

With that, I'm going to guess that pump is bad.

She wants $450 to sell the car. Should I buy it, put on a pump and resell it? It's in pretty good shape. Or, would the risk of it having potentially been overheated be too much?

Let me know what you guys think.
Jon

If shes selling the car for 450 and nobody wants to mess with it give me a ring at 309-224-8777 if your around peoria. I will come pick it up

She lives close to Nevada Taxi.

hmmmmm........... yeah lets scratch that last comment then.

Huh?! I'm confused!!

No problem, Jon. Glad we got her all straightened out.

Okay, I thought I'd update you guys a little. I decided to just go ahead and buy this car from the girl who owned it. She only wanted $450, and I figured that even if I can't make it stop overheating, I can always part it out and get my money back. Probably more, actually. Didn't do a whole lot to her yet. I went to a couple of concerts out of town this weekend, so that absorbed most of my weekend. It was worth every minute, though. Sevendust Rocks!!!

Anyway, I went out to play with her a little bit today. Didn't get a chance to do too much, but I did tinker around a fair amount. The first thing I did was to take off both the PS and the Alt belts so that I could play with the water pump pulley to see if the bearing was bad or the shaft was messed up. It didn't feel like anything was wrong to me. Spins freely, makes no noise, and has no play. So, I'm guessing the bearing is okay. I didn't take the timing cover off to inspect the weephole, but there's no evidence of leakage anywhere below, so I'm guessing the seal is okay as well. This leads me to believe that the water pump is okay.

Next thing I did was to pull out the dipstick to see what color the oil was. It didn't appear to be a milkshake to me. In fact, it was quite black. Could use a changing. It was about a quart too full, so that's a problem. I also started her up to check for white smoke from the exhaust pipe. Didn't see any of that. So, I'm feeling that she's doesn't have a warped head or bad head gasket.

My next step was to check the coolant level. I opened the filler cap and couldn't see any coolant at all. I had an empty two liter soda bottle that I filled with water in order to fill up the system. I was going to use Anti-freeze, but I ultimately decided not to, considering that I might have to dump it all really soon if I find out the the water pump or thermostat is in fact defective. I'll definitely change that before winter hits no matter what I figure out. It took almost 2/3 of the bottle to fill it up, but that was before I drove her to get out the air pockets. Oh, and I also forgot to check the level of the overflow tank.

The next thing I did was start her up. I let her idle for quite some time (maybe 20 minutes), and the needle stayed right where it was supposed to be: pointed pretty much straight up to 12 o'clock. I didn't notice at this time whether or not the fan was cycling on and off. However, since it wasn't running anywhere near hot, I was beginning to think that maybe the only problem was that the coolant was low.

So, I decided to take her for a spin around town to see what happens then. That's when trouble started to come into paradise. I didn't take her on the highway at all. In fact, I probably didn't get much over 35 mph. She started to get hot, though. I don't think I'd driven further than a mile and the needle was starting to approach redline. When it got close, I turned onto a side street and shut her down with the intention of starting and stopping the engine to coast home. I shut her down the first time and coasted a ways. Then, I restarted her, and was able to make it all the way back home without having to kill her again. She was starting to warm up, though.

When I got back to the house, I decided to let her idle to see what she'd do. She cooled back down to normal operating temp (12 o'clock) and stayed there the whole time she was idling. I let her idle for probably another 10 minutes. I also noticed that the fan was cycling on and off as it was supposed to. After a while, I decided to take her for a spin again. Once again, it didn't take long for the needle to approach redline. This time, when I turned onto the sidestreet, instead of shutting her down, I pulled over to let her idle. Once again, she cooled down to normal operating temperature and stayed there. It took about 10 more minutes for her to cool down.

When I got back, I shut her down long enough for her to cool, then opened the radiator cap again. The coolant level was down again, but it didn't take much to fill her back up. I also decided to check the overflow tank. It was pretty close to empty, so I filled it up as well. All told, it took about 1 1/8 2-liter bottles of water to fill up the cooling system. For you non-metric types, that's just a shade over half a gallon of water.

So, what do you think? Since it cooled down to normal operating temperature every time I let her idle, I really don't think that the water pump or the thermostat are bad. I also think that the coolant switch for the fan is okay, since the fan was running. But, the fact that it would heat up when I'd start driving puzzles me. Do you guys have any idea as to what you think would cause this? Any suggestions you could give would be greatly appreciated.

Thanks for reading. I appreciate all of your guys' time.
Jon

Do you guys think a leaky radiator cap would cause it to run hot? I know people often neglect that part of the cooling system.

Jon

All right, guys... I think this car might have much bigger problems, and maybe I shouldn't have dropped $450 on her. I've owned it for two days, and already thinking I should kick myself in the ass for squandering my cash.

First off, I decided to pull the thermostat out of her to see if I could keep her cool while running down the road. And, before you ask, no I wasn't planning on leaving it that way. I know it's not good for the car to run it without a thermostat. Anyway, the first thing I noticed is that there was about 1/8 inch of gunk on the thermostat all the way around the opening. I didn't think it was motor oil, but to be sure I ran down to a local radiator shop to ask them what they thought it was. The guy told me what I thought he would. He told me that he thought it was stop-leak. Like Bar's or something similar. Evidently, this thing started leaking, and rather than fix the problem correctly, someone threw a bunch of stop-leak in the cooling system.

So, this presence of gunk leads me to believe that the inside of the radiator looks the same.

Anyway, after I took out the thermostat, I decided to take her for a drive and see if she ran hot. At first, she did okay. It ran for a couple of miles (city driving) at normal operating temperature. By that, I mean that without a thermostat, it ran at the temperature it normally runs at with a thermostat, not less, as it should have if the thermostat were the problem. I let her idle while talking to the radiator guy. It still did fine. Then, when I started coming back home, it started getting way worse. The guage pointed to the start of the red line, so I shut her down. I decided to limp her home by starting her, getting her up to the speed limit, then shutting her down, taking her out of gear, and coasting down the side streets. I made it home this way without overheating her.

So, anyway, there's no water in the oil pan, and no oil in the cooling system. However, the radiator guy told me that what these things do when the head gasket goes bad is leak between the combustion chamber and the coolant system. So, the compression increases the pressure in the cooling system, forcing coolant out (usually by creating new leaks in the cooling system). The only upside is that I can find no evidence whatsoever of cooling system leaks. Not surprising, considering that there's an eighth of an inch of stop-leak in there.

So, let me give you my logic, now. If you guys see a fault, point it out. If you have another idea, shout it out. If you agree, give me some words of encouragement. I'm thinking one of two things: bad head gasket; or so much stop-leak inside the radiator that neither the fans nor the air coming in at driving speeds can begin to cool the water. Since there is no coolant/oil exchange between the oil and cooling ports, I'm thinking that with a compression test, I'll be able to tell if the pressure is leaking back into the cooling system. Also, if I did a compression test with the radiator cap off, wouldn't I see bubbles shooting up through the water at the filler hole? Pressure will release at the point of least resistance. If I have the cap off, that will definitely be the point of least resistance.

If I find no head gasket woes, I would think that I can assume that the stop-leak is the culprit. Is there anything that I can run through there to get rid of all that shit? I don't think that just flushing it will drive that stuff out. If not, I'll just replace the radiator and see if that helps it run cooler. No, not with a new one. I'm not going to take that big of a chance.

One more thing of note. When under load, there's a bit of a rattle coming out from under the hood. Can't tell where it's coming from. It doesn't do it when I rev the engine. Only when under load. Not sure what it is. It's not really a knock. Not loud enough. Like I said, it's a bit of a rattle. You know, it almost sounds similar to the rattle a diesel engine makes when operating normally, though not near as loud. What do you guys make of that?

Thanks again for your help, fellas. I appreciate anything you can give me.
Jon

P.S. I hate all forms of stop-leak. They're evil. They should be eliminated to force people to actually fix problems that arise rather than just putting a band-aid on something that needs a tourniquet. I think that they were invented by and for people that want to mask a problem before they rip off the next owner of their car.

Get a compression test done on it. If that yields no real results (as mine showed 130psi across the board but it was a freshly rebuilt motor) then it's still not safe to say that the headgasket is not the problem. The only way I fixed mine was to throw a barrage of parts at it and pray to God that it fixes it. The 160* thermostat was finally what fixed it for me after having two different thermostats in it before. I did a headgasket, ARP headstuds, milled head, all new hoses, brand new radiator, fans running full time, AC eliminated, and new water pump and it still ran hot. I finally put the 160 stat in it and it runs at a constant 172*.

This overheating job is going to take a backseat for a few days. The holiday will delay me some, but I'm going to spend most of the weekend putting my stolen car back together. Once I'm done with that, I'll resume the task.

Thanks for all your input. I'll let you know what's up once I get back at this one.

Jon

when was the timing belt tensioner last changed? I noticed you said it sounded like a diesel engine, and thats what mine sorta sounded just before my tensioner went bad on me. Your tensioner can make your timing belt slip a tooth or more and make it sound like that too. Ive already had mine slip on me out of the blue by a tooth and it would actually run ok, just wouldnt build boost and sounded like a diesel engine. If your timing starts to go off, cant that also make you overheat?

Just another theory to add since you said it was making that noise.

Can stopleak also clog up water passeges in the motor? Might be a flow problem causing it too

All right, I know it's been a while, but I was finally able to play around with this thing again. I took it to my buddy's mechanic shop, and it didn't take long for us to determine that the head gasket is shot. Problem is, I'm moving back to San Diego next week to return to grad school, so there's no way that I'll be able to work on it. So, I think I'm just going to get rid of it and try and get my $450 back.

How would you guys recommend that I go about this? Is eBay a good idea for a car that doesn't run (at least not correctly)? Or should I stick with the local papers? The car itself is located in Lincoln, Nebraska. If you know anyone close who's interested in the car, let me know. It's a 1992 Talon Non-Turbo 2.0 Liter. The car is quite decent. Pretty nice shape and not all that high of mileage. If someone has the time to put a little TLC into it, it'll probably work out nicely for them. I don't have the time and I already have a DSM that I'm in love with, so this car is expendable to me. If you know anyone who wants it, let me know. Have them drop me a line at jhieb1@hotmail.com or call me at (402) 770-1118.

Thanks
Jon

Step one would be posting this up on the Exchange. Lots of cheap DSMs to be had lately. Ebay may prove fruitless, but if you're just trying to unload it, I'd use all available means.