Car Overheated / Overheating / Overheats [MERGED]

[NTRCOOL]

OVERHEATING? The issues and their solutions have remained the same- either you don't have enough cool air reaching the rad, there's a cooling system obstruction which is preventing coolant from circulating, or your head gasket has failed and is allowing coolant to be consumed or pushed away from the engine.

Discuss all possible overheating problems and solutions here.


OK,
I just left my house to go over to my GF's,and happen to look down and see my needle right before the red mark. This just happened out of nowhere. I stop the car as quickly as i can, and pour in some coolant(Coolant a little low). Still same thing. Welp im in the middle of the road, and HAD to get it home. Im only 5 min from my house. I decided to try and make it(I really had no other choice). Welp I drive no faster than 20mph, and the temp needle is BARELY into the red the whole way.And occasionaly to the left of it. Am I ok?? Do ya think any damage was done?? And im thinking either thermostat, or water pump. For each of those, whats a round about $$ figure to get replaced?? Any info you have would be GREATLY appreciated!

 

[Michael Z.]

Do a compression test. If it's the headgasket, two adjacent cylinders will have noticeably lower results.

When you said that the Felpro was all wet, when did you check it? If it was after you removed the head, it's going to get wet as soon as you loosen the studs. Did you have the head decked when you realized it was warped?

Anyway, I noticed your car is a 90. If you still have the original rad in there, I'm guessing your 16-17 year old rad just isn't cutting it anymore.

 

[92lzerNA]

Yes I did have the head decked, cleaned and a valve job done to it.

 

[beating4g63s]

I'd check the raidator and radiator cap to see if the radiator is not clogged. also check your oil to see if it's kinda milky thats one sign of a bad hg.

 

[92AndAHalf]

Mine was doing the same thing and I found that my radiator was clogged.

 

[pballer]

I would of put the damn thermostat back in because it acts a restriction in the system so that the coolant has time to transfur heat to the rad and not just get pushed right back into a hot motor. Not running a thermostat CAN cause overheating.

 

[telnut]

Are your electric fans coming on? When you run your heater you are im effect adding another small radiator to the system, hence tempreture may drop slightly. I have flushed radiators and knocked enough stuff loose to clogged radiator. How was it flushed? I prefer reverse back flush with machine if it is in car. The best flush is to pull radiator and have it checked at radiator shop. A plugged radiator is not an uncommon problem on DSM. If the cooling systems has not been serviced regularly a restricted radiator is a good bet.

Telnut
"Motor oil in my veins, nuts and bolts in my brain."

 

[92lzerNA]

When I flushed it I just unpluged it and ran a hose water though it untill the water came out clear. I replace the cap when I changed the thermostat. Yes my electic fans are coming on.

 

[chicagoavenger]

I would of put the damn thermostat back in because it acts a restriction in the system so that the coolant has time to transfur heat to the rad and not just get pushed right back into a hot motor. Not running a thermostat CAN cause overheating.

You know I keep hearing that alot lately but it seems all the searches I have done say the opposite. I threw in a new freeze plug and will bolt everything back so we will see what happens.

 

[Madmax82]

Hi,
My Talon ESI with a 420a engine is overheating 3/4 at idle before the radiator fan kicks in, this doesn't happen if i turn on the a/c.
What could this be, i replaced the thermostat (OEM); flushed the system, cleaned the radiator and the HG was replaced.

 

[xveganxcowboyx]

You probably have a bad temp sensor or bad main fan. When you turn on the AC the secondary fan stays on. This is what is keeping your temp down. I'm thinking your main fan is not coming on, because it is dead, in which case you need to replace it or because the temp sensor is faulty in which case it needs to be replaced.

I'm not sure what the best way is to test the fan. Either applying direct power or using a volt meter/test light once it's warmed up. Hopefully someone else can chime in on this.

 

[Madmax82]

When the temperature is at 3/4 the main fan comes on and turning on the A/C both fans come on.

 

[stuckwithgsx]

you did check your coolant level and it's good right?

 

[Madmax82]

yes the coolant level is ok, there is no air in the radiator.

 

[Bodack]

I had this problem a while back and I've wired it to fix things. My problem was the thermo fan switch relay whatever. It's located at the bottom of the radiator I think on the opposite side of the drain plug. The unit itself looks just like the sensor on the thermostat housing area. The Haynes manual tells how to test it. Yours may still be working, just going bad. Test it anyways.

 

[Madmax82]

But i belive that you are talking about the radiator of a 4G63 x because my radiator for the 420a doesn't have any sensors at the bottom.

 

[xveganxcowboyx]

It should come on before 3/4. Halfway or about 190 should be the trigger point. Maybe lower on the 420A. The secondary fan should come on at 200 or 210 (or something similar).

 

[htamotorsports]

Ok so ive searched and have read plenty of threads about overheating, but my situation seems a bit different.

The car overheats in under 8 mins at idle with the fan on(hardwired fan)
-hardwired fan runs the whole time
-new thermostat
-new radiator
-neither the upper or lower radiator hoses are warm
-not very warm heat

but when i take out the thermostat the coolant underneath is very hot


Then i ran the car(idle) w/o the thermostat
-both hoses warm/hot
-doesnt overheat
- gauge sits a little below 1/2
-warmer heat

compression numbers 150,120,135,150, so im thinking its my headgasket right between cylinders 2/3

but when i poor a cap full of oil in 2/3 the compression jumps up to 150/160, which makes me think that its not the headgasket but just bad rings.

PLEASE HELP!

 

[chrisfullwood]

you've answered your own question, it overheats with the thermostat in, and doesnt overheat with it out.

check the thermostat...
something is stopping it from opening and circulating the coolant. thats my suggestion.

 

[sawnuoff]

put it on the stove with boiling water to see if its opening, if its not boiling over i would hook up an external temp. gauge.

 

[harith444]

Let me start by saying you guys are amazing, very good advice, thank you!

I'll start with what's wrong and what I've tried so far to fix it. Under boost, up hill, and slightly on the freeway the temp will start to climb. Logger says from 200-219f. This is no Subby. I shouldn't be runnin' 220's. Too warm. When going down hill for long periods of time, the car will drop temp like crazy... around 140f. I'm thinking because of the holes i drilled in the thermostat.

I've flushed Radiator, new Mitsu 88C thermostat with two holes drilled in it(another thread suggested it), 50/50 coolant water mix, fan works. I'm deathly afraid of it being a warped head, or bad HG... or both. Compression test looked good, about 170-173 across all the cylinders. And I'm currently looking for somewhere to buy a hydrocarbon tester... but no luck. I've run out solutions besides a head reconditioning and I've researched all over the site so finally I decided to post. This is my first one so if I left anything out that you'd like to know, just holler. Thanks so much guys.. let's get her fixed. I wanna drive her normally again without watching my boost.

 

[Madmax82]

A friend of mine had that problem, he replaced the water pump and it fix the issue.

 

[harith444]

It seems to be flowing just fine though.... with those holes in my thermostat I can see the fluid flowing with the cap off as I rev under the hood. I will definately check it.

 

[toybreaker]

Overheating while moving can sometimes be caused by obstructions in the airflow thru the cooling system, more specifically, the radiator.

. The a/c condensor fins can be damaged, blocking the airflow.

. The radiator core may also have some bent/damaged fins. Another thing that happens on these cars is that the radiator fins catch the stuff that gets thru the a/c condensor, as the radiator is thicker, and has a finer pitch fin structure. There's times the radiator gets blocked with yak hair, pebbles and the like, and yet the a/c core looks fine from the front. You can shine a strong lite from the engine side of the cores and eyeball how things look from the bumper opening.

. If it looks obstructed, just removing the radiator, laying it flat, and backflushing the fins (gently) with the garden hose can make things good again. You can also shoot the a/c core with the hose (while it's still installed) from the backside at the same time with the garden hose from the engine side of the core towards the bumper. You'll be amazed at what comes out.

. Do you have a front mount intercooler blocking the airflow into your radiator?

. The ducting between the radiator support and the front bumper can get removed during repairs/maintainane and not reinstalled. This lets airflow around the core instead of thru it, leading to overheating at speed.

. Your timing at the cas could be incorrect, leading to incorrect ignition timing, which can also cause overheating.

How does the car run?

Are there any other mechanical issues?

Those compression numbers look kind of high for a 1g,..(or maybe I'm only used to checking worn out, pos, motors at a high altitude)

EDIT: Just saw the evoIII motor in your profile. Has this motor ever run right/cool in your chassis?

 

[harith444]

My timing is at 8 degrees or at least that's what my logger says. This motor ran at a perfect tempature and held it pretty firmly up until a month ago. My mechanic high fived me and told me those are almost perfect readings on a compression test for a 4G63, but we could be wrong, I'll try to find out what they should be from Mitsubishi.

No front mount and duct is still there.
Nothing mechanically wrong with the car besides my TPS likes to turn off and back on.
And I would say it runs really well.

Tomorrow is a day off! I will check the Radiator, take it out, clean any obstructions I might find and I will update. Thanks so much for the reply!

I checked the Radiator, cleaned it, and flushed it once more, there wasn't much to clean but none the less. A/C condensor was a bit worse, yet not so serious. So both clean and still warmin' up.
I'm just getting home from a canyon run with a friend... sprung a mystery leak. WTF
It was almost normal going up, warmed up to 206F and soon as I started boostin' a little, temps shot up to 223F. So now I'm not really sure as to what I should do.

 

[toybreaker]

My timing is at 8 degrees or at least that's what my logger says.

The number the logger displays is not necessarily the actual ignition timing at the spark plugs. It's what the ecu thinks it is.

The actual timing is a function of the base timing + ecu advance.

Base timing is adjusted by rotating the cas relative to the cylinder head.

There is an excellent write up on the procedure for checking/setting the base timing in the v-faq's.

Base timing is something I think a lot of people overlook when there's cooling system issues, At any rate, I think it's something worth investigating when troubleshooting a problem of this nature.

Can you give a litle more background on the swap, miles driven, and any other problems you've had with it?

Have you been using the same logger/software set up the whole time?