need expert help on overheating

Well. I acquired a 94 sl auto that was overheating. it was owned by a mechanic that said the headgaskets were toast. no problem. so after changing the head gaskets and water pump. put it back together still over heats.changed the radiator, took the tstat out, and changed the cap. still overheats. changed the little temp sending unit and the center gauges. still overheats. figured the heads were warped. took them off. went and got them resurfaced (they were warped. one was 8 off an the other was 12 off) dipped an pressurized. all back together an the damn thing is still overheating. wtf am i missing here??? It only drives about 8 minutes before it decides to overheat. turning the heat on wont bring it down.i dont have the ac on while driving it. BOTH fans are on while its overheating. I just dont know whatelse it could be and im getting aggervated with it. PLease tell me theres something else that could cause overheating. one thing i have noticed. I have a 92 sl that i toook the tstat out of because it was overheating too. and now when i drive it it takes a good 20 min of stop and go traffic for that thing to get up to normal driving temp. this 94 i got. gets up to normal driving temp in 3 minutes, kinda strange.

I need help. please

The thermostat is essential to the coolant system.

with it not being in there would not cause it to overheat

Coolant is forced to the radiator by the thermostat.

http://www.stealth316.com/images/stim/tim_07-02.gif

still overheating. anyone got any suggestions??

Get an infrared laser from a parts store and while the car is running, point the laser at different parts of the cooling system. Doing that should give you an indication of where your problem may lie.

Have you pressure tested the cooling system on the car?

You may possibly have a blockage in the cooling system or inadequate flow. If the fans are working and youve got a solid sealed system with no thermostat, and a proper mix of antifreeze and water, I don't see why the car would overheat other than improper circulation.

There HAS to be some blockage somewhere. Try reverse flushing the motor.

Buy.com - PRESTONE Flush & Fill Kit

SUPER RADIATOR FLUSH -- 22 OZ. | The Auto Alley

Go to auto Zone, etc

Good luck !!!!! :D

Quote:

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Originally Posted by mb3000

Coolant is forced to the radiator by the thermostat.

http://www.stealth316.com/images/stim/tim_07-02.gif

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Not exactly. Coolant flows into the radiator when the tstat opens. The tstat doesn't force the coolant in.

Removing the Tstat can also overheat the car. If the coolant is constantly flowing through the radiator and has no time to cool down, then the radiator can't do its job properly.

I'll take a stab here and say that the engine has had stop leak in it, due to the head gasket issue. Were all the water jackets properly cleaned when the heads were off the block? Is the system properly pressurized at ~15psi? Is the water pump new?

im buying a laser thermo and a pressure test tmw. Im gonna switch the radiator (again) and the coolant temp switch to see if that will help. doubt it tho. radiator was fine in my 92.

I have never seen a car overheat without a thermostat. but ill put one in a see how it goes. It boggles my mind that this car gets up to normal driving temp within 3 min of runing. Without a tsat it should take it a good 20min of stop an go traffic for it to reach temp.



97 vr4. Im not sure if the guy before me put stop leak in. But yes. The heads were dipped resurfaced pressurized. all the good machine shop shit was done

water pump is new.
and how would i tell what the system is pressurized too???

Thanks guys for starting to chime in. I need the help

Quote:

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Originally Posted by triggerman454

There HAS to be some blockage somewhere. Try reverse flushing the motor.

Buy.com - PRESTONE Flush & Fill Kit

SUPER RADIATOR FLUSH -- 22 OZ. | The Auto Alley

Go to auto Zone, etc

Good luck !!!!! :D

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I'm thinking this, don't listen to people telling you your car is overheating because it doesn't have a thermostat please. It can cause hot spots and you should have one but it isn't your problem. Drive it a little, then pull over and turn the car off and pull the key out. If you can feel the radiator see if it has cool spots in it. If the top is hot but the bottom isn't then you know it's blocked. If you can't get to the radiator (I know it's tight) then you can check temps with one of these.

http://www.google.com/url?source=img...FW-vRzRtsBSYmA



Also pull the rad cap off when it's cold and rev it a little bit. If water rushes out you might have a head gasket leak or a cracked head. I wouldn't be shocked if the head was cracked.

Quote:

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Originally Posted by x2xtreme360

Not exactly. Coolant flows into the radiator when the tstat opens. The tstat doesn't force the coolant in.

If the coolant is constantly flowing through the radiator and has no time to cool down, then the radiator can't do its job properly.

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And at the same time the coolant doesn't stay in the engine long enough to heat up. I had a broken tstat and the car would only get warm at idle. At cruising speeds the temp bottomed because of the free flowing coolant.

At the same time I have seen some cars that absolutely need a thermostat or they will overheat. 3s's are not one of those cars though.

You can get a cooling system pressure tester from advance auto or autozone. They may have it for rent or you can purchase it as well.

Leaving the thermostat out of the equation isn't a bad idea at the moment.

When the car gets to operating temperature, does the heat work inside the car??

i have left the cap off, water doesnt blow out. If the heads were cracked im 100% sure my head guy would have found them. hes very reputable.

when the car starts to overheat the heat still works. sometimes it will go luke warm, than back to hot but never gets cold. stays pretty hot for the most part.

Im on my way to buy a coolant temp sensor an swap the radiator again.if that doesnt work than we will get a pressure test.

update, the coolant temp sensor wasnt the issue. it got to normal temp in the same time. so im taking that back.

I did take the cap off an let the car idle from cold, to normal driving temp. it never bubbled over or rushed out until i held the gas at 3rpm for about 5 seconds. than it gushed out but only until i let off the gas. also i noticed the top radiator hose is significantly hotter than the bottom. also noticed that right side of the radiator was wayyyyyy hotter then the left side. Im gonna swap my radiator again, an see what happens

Did you change the water pump?

Quote:

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Originally Posted by mtpockets20

update, the coolant temp sensor wasnt the issue. it got to normal temp in the same time. so im taking that back.

I did take the cap off an let the car idle from cold, to normal driving temp. it never bubbled over or rushed out until i held the gas at 3rpm for about 5 seconds. than it gushed out but only until i let off the gas. also i noticed the top radiator hose is significantly hotter than the bottom. also noticed that right side of the radiator was wayyyyyy hotter then the left side. Im gonna swap my radiator again, an see what happens

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Cool, you are figuring it out. I swapped a bad radiator for a bad radiator before on one of my RX7's. If you got cool spots then you know there is a problem. If the one radiator hose is that cool you might have the blockage in the engine. It pretty much has to be one or the other.

Keep checking temps, good luck :)

thanks for words of encouragement. I know there isnt a blockage in the heads. how the hell would i get a blockage out of the block??

f this car. radiator didnt do shit.

As Hans asked, did you check/change the water pump?

yes. im gonna order another and change it again. than im calling it quits.

are u sure u dont have any leaks? around the cross over pipe o rings? i remember having a similar issue until i replaced the cross over pipe O-rings.. Coolant would get stock between the heads.. so i never was able too see the leak until I got cross over pipe O rings replaced.

Make sure you are using coolant and not water.

those o-rings get them from mitsubishi dealer. they are like $10. dont get them from 3sx or autozone.. get them from the dealer!...those sre the right thickness.

3SX sells OEM Mitsubishi parts...

How about you drain all the water/coolant out and cap the t stat on one side with a gauge and pump air into the other. Check the air pressure on the return from the block.

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