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Car running TOO HOT...now it's my turn!

4K views 11 replies 6 participants last post by  rcoltrane 
#1 ·
Ok, after following the Techboy soap opera with his engine to try solving a nasty heating problem ("http://www.dsmtalk.com/forums/show...ww.dsmtalk.com/forums/showthread.php?t=250522, here I am with the very same problem. But since I cannot afford to open my engine up to have my head checked/serviced yet, I'm taking the 'cheap' road and started checking the most obvious things and replacing cheaper parts first.

Here's what I did so far: I did a major radiator clean up, replaced the old water/fluid mixture, making sure that there were no air bubbles in the system, did a pressure test to check for leakage and it revealed one weak spot in one of the hoses so this hose was replaced with a new one, replaced both thermostat valve and pressure cap with OEM quality Mitsubishi parts taken from JNZtuning (stock parts, my car is 100% stock), checked the radiator fan and it's turning on when the coolant temp reaches 190F, the radiator fan is blowing in the correct direction (I did the piece of paper test and it was being sucked when I put it in front of the car while the fan is blowing the engine, so the air is flowing through the radiator as it should).

And here are the points where I think the problem can be, since these previous actions didn't solve the overheating problem:

- My water pump was replaced 3 years ago, but it's an aftermarket part and I don't even know the name of the manufacturer, so I know nothing about its quality. I don't hear any strange sounds coming out of it so I guess it's operating, but I don't know if it's flowing the required amount of coolant through the system or not. Since it's a belt-driven pump, the flow increases with the car's RPM. But when I increase the RPMs, the car gets hot faster!

- both coolant temperature sensor (that sends info to the ECU) and the gauge temperature sensor are very old and were never replaced by myself. My mechanic did some tests on it and it seems that the coolant temp sensor has wrong readings (it's sending lower temperature readings to the ECU). I did a clen up at the gauge sender sensor and It's giving different readings at the gauge now, it seems to be more precise than before. But I'll replace both of them ASAP with new OEM parts as well.

- Since my engine is operating at an average temperature of 278F (YEAH...WAY TOO HOT I know) for quite some time, I guess that my headgasket is gone!). My car warms up way too fast (It takes only 5-6 minutes in the morning to heat up! And every time I accelerate at moderate uphills, it starts heating up quite fast. I've read all the HG testing procedures that I could find, but none of them are actually ocurring in my case. No air is leaking through the combustion chamber in the water system, no water in the oil and no coolant loss being burned in the combustion chamber. The only clue I have that would point a finger to the HG is the faster warming up. The head has stock measures and has never been serviced before. When I had the engine opened up in nov/2011, my mechanic did a head measurement and it was flat plain, so we didn't take it to a machine shop to have it serviced. We then replaced the headgasket with an OEM Mitsubishi headgasket and that's all.

Clues? Thoughts? Tips? What would you do first in this situation?
 
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#2 ·
Well, I think you're probably correct in assuming it's the head gasket. That's all it was in my case. My head wasn't warped, I just sent it out to be checked to be sure. I can tell you if you continue to drive it with high temps like you will eventually warp the head and then you'll be into some real expenses.

If you're reluctant to do anything major right now b/c of money, try this ... pop the valve cover off and check the torque on the head bolts. If you're running to OEM head bolts it's torque to yield, if your running ARP's the suggested is 90 ft. lbs. When you motor was apart in Nov/2011 and you put the the new OEM gasket on, did you re-torque after the initial warm-up? My guess is no, so I'm thinking you might not be at spec anymore and your getting air in the system under higher load/RPM"s (like going uphill). Torquing the head back to spec might buy you some time, it might not. Either way, unfortunately, your hand will eventually be forced. Usually when a headgasket starts to go, it doesn't take too long before they completely go. Hopefully you can get through this without doing damage to the head.

EDIT: Oh, and one last thought .... I did a lot of reading when I was going through my issue on water pumps. The consensus seems to be (IMO) either go with an OEM one, or a GMB seems to be acceptable. Anything else is suspect, in inferior castings, different impellers, yada, yada .... You can get an OEM through JNZ or Extreme. GMB's are a bit cheaper. If you do end up having to pull the head down the road to replace the HG that would be a good time to get a reliable pump on there since you'll have to re-time the car anyway.
 
#3 ·
The first thing that I've heard recommended is an industrial-strength (not a garden hose) flush of the cooling system to try and remove any crud in the system. Something else inexpensive is to add "Red Line 80204 Water Wetter" to the coolant. ($9.99 at AutoZone) It may just buy you some time.

Redline's claims (note that they say it works best w/ plain water, which is a no-no in freezing weather):

  • Decreases engine temperature by up to 30 degrees
  • Provide rust and corrosion protection in plain water for racing engines
  • Designed for modern aluminum, cast iron, copper, brass and bronze systems
  • Improves heat transfer
  • Prevents foaming
http://www.redlineoil.com/product.aspx?pid=74
 
#4 ·
Once the car is up to op temp, have you popped the rad cap off and checked for coolant flow/movement?
With the thermostat open, and the rad cap off you should see the coolant move, if id doesn't I would suspect the impeller on the water pump rusted away or the shaft failed.


With the car off, remove the rad cap, then start the engine, look for a geyser out of the rad.

So you loose no coolant (fluid level is correct n you do not have to add)
Burn no coolant (no white smoke out the tail pipe)
No oil/water mix (oil is clear and not looking like coffee with cream)

Also what are the AFRs? If the fuel pump is weak, or the fuel injectors partial clogged, that may put you lean and cause you to run hot some too.
 
#5 ·
Here's something else easy you may want to consider doing if you have a capability. A fan override switch. I just did this myself when I put my car all back together - it's super easy to do:









Here's how to do it. Get a normal SPST switch. The red wire on the right goes to the ECU. When you take the drives side console trim off you'll have easy access to it just by the gas pedal. Splice the red wire into the fan relay PIN 20. It's the 7th one up from the bottom on the rightside - green w/ orange stripe. The black wire on the left ... just run that to a ground somewhere. Wah-la. You're done.

The ECU still has control over the fans, but you can turn them on anytime you want to. Works in the ACC key position, but not with the key off - which I like b/c you won't forget - leave them on - and kill your battery. :mad:

Again, this isn't gonna solve your problem - but it can help keep things cool.

SIDE NOTE: You can also splice into PIN 21 just above it, that'll do just the primary. PIN 20 turns on both.
 
#7 · (Edited)
Here's an update:

My A/C fan motor died and I took it to the shop for repair. If it's broken beyond repair, it will be replaced (remember I'm in Brazil, parts here are VERY expensive and take a month to arrive!).

I was running without the thermostat valve for 5 years now. Bought a new OEM thermostat valve to put it back in the system, since I decided to fix this thing for good. Also, I've replaced the cap and both coolant temperature sensor and the sender unit at the thermostat housing with new OEM parts. With these sensors / cap replaced, I've got everything checked... at least all things that are 'out' of the engine.

Things I've inspected so far:

- cooling system pressure - ok
- cilinder compression test - ok
- new NGK spark plugs with the correct OEM gap - ok
- radiator / hoses are clean with no restrictions and/or leaks and flushed - ok
- cooland replaced with 50-50 mixture of distilled water and refrigerant - ok
- no bubbles/air in the cooling system - ok
- fluid levels - ok
- Oil has been changed two weeks ago and has the correct color with no signs of water on it - ok
- temperature sensors - ok
- radiator fan blowing at the correct direction and kicking at the correct temperature - ok
- A/C is working properly, with hot air and cold air - ok (turned it off until I get my a/c fan motor back)
- Water pump is working with no leaks - ok
- ignition timing at 5btdc - ok
- TPS at 9,8% when idling

BUT... unfortunately, my car is still overheating. And when the engine is at the optimal temperature, I can see a little (very little) amount of white smoke coming out of the tailpipe when I accelerate.

So I guess that:

1) I have a warped head

OR

2) I have a blown headgasket

OR

3) Both :/

One more thing I'm going to check is the catalitic converter. Since I was running without the Thermostat valve for 5 years, I certainly was running rich, which produce carbon deposits in the catalitic converter, so it may be clogged after all these years. Since 36% of the total heat is eliminated through the exaust, if it's clogged, this heat could go back to the engine or the engine wouldn't get rid of the heat as it should. I don't know.
 
#10 · (Edited)
Quick update:

Today I did one thing I was overlooking and it can may be the problem...

SInce my car was running without a thermostat valve, I've installed a new OEM part. This morning I did the 'hose' test and I turned the car on to wait it to heat the engine up to the operating temperature while holding the upper hose to see if my new thermostat is operating accordingly. WHen the temp needle went to the very middle in the dash, the thermo valve opened up and started throwing the hot water to the radiator and the upper hose got very hot almost instantaneously. HOWEVER, at this point, the fan didn't kick in and It took AGES to kick for the first time!

Now my question is: Is this the correct behavior or the radiator fan should kick in immediately after or togheter with the thermostat opening??

I have a "T" temperature sensor installed at the upper hose since I bought this car and this is currently the sensor which kicks the radiator fan using its own rele. The temp sensor located at the bottom of the radiator is still there but it no longer works or was disabled when this new one was installed. I think that it should kick the fan at the very moment the hot water starts coming through it inside the upper radiator hose, am I right?

And my car is not burning coolant. The car is not lowering the coolant level and I can see no white smoke coming out of the tailpipe, the engine could be cold or it could be some little amount of 'blue' smoke because my car is lowering oil for sure, but not coolant. So please ignore this observation on my previous post.
 
#11 ·
The fans shouldn't kick on as soon as the T-Stat opens up, it shouldn't come on until temps are over 200 (not sure on exact temp), otherwise, there wouldn't be consistent coolant flow through the radiator/engine. T-Stat opens up at 180 or 190 depending on which one you have.
 
#12 ·
Mine is stock, which means 190 I guess. Thanks for the explanation.

Now I'm thinking on replacing my radiator. It's not the stock plastic model anymore and has no leaks but I don't know the manufacturer of this one that I have or how many rows it has. It's not made of aluminum for sure. Also, when I took the A/C fan off the car, I could see plenty of bended dents at the inner side of the radiator (fan side).

So, which one would you guys reccomend for my 93 A/T Eclipse? I've found some brands but they all say that their radiator only fits 1st gen Eclipses with manual transmission ONLY, mine is automatic. But AFAIK, the front end where the radiator goes is the same for both auto/manual engines.

Here are the ones I've found so far:

"http://www.ebay.com/itm/ECLIPSE-LA...993|Model:Eclipse&hash=item4d2ecd4e9b&vxp=mtr

"http://www.ebay.com/itm/2-ROW-FULL...993|Model:Eclipse&hash=item2ede815370&vxp=mtr

Advices are appreciated on this subject.
 
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