Over heating question

[soulweaver]

Ok I know there are a thousand questions on this subject but I can't find one like mine. I replaced the cylinder head, and thermostat about 3 months ago to start things off. The car has only gotten 100 miles on it since. I got it legal yesterday and noticed a leak on the top radiator hose. So I replaced that and noticed my car getting really hot. Then all of the sudden it went back to normal temp in the matter of 5 seconds. So I kept driving and watched it go back in forth for about 10 miles and finally pulled over and replaced the thermostat at a local parts store. I then take off and the car is really over heating now and it stop jumping all over the place. But I did notice that the car cools down really fast. Any idea's?


Sorry if i didn't explain this good enough.

 

[jrohner]

Sounds like you've got air in the system.

Let it run and get warmed up with the cap off and the heater on, that's what I do to get the air out. Make sure you have plenty of coolant in the recovery tank and that you have a good hose going to the tank. Get a new radiator cap also if you haven't recently. Pray that your head gasket is not leaking.

 

[soulweaver]

Man I hope so. I couldn't make it home in it and I took it to Lucas Smith Dodge here in St.Louis. So I hope they say it's air in the system and not a blown head gasket. Could there be anything else that it can be.

 

[ndsti]

Yes, it could be the temp sensor, reading a false positive. How did you verify that the car was overheating? Have you checked your coolant level?

So far you have replace most of the components that would help you, except the temp sensor. If your head gasket was blown you would smell it at your exhaust pipe and you would be losing coolant.

 

[soulweaver]

Well i replaced the coolent temp sensor and I don't know what it would smell like and I havn't noticed any loose of coolant but I only got one hour with the car as it started to mess up. So I really didn't have the time to look at everything.

I looked at the gauge on my pod to see if it was over heating and it was right on the edge of the red. I cut the motor off before it got on the red. Is there any other way to tell if the vehicle is over heating other than the gauge?

 

[ndsti]

If your burning coolant it has a sweet smell when burnt.


When the car gets hot again get an Infrared thermometer and find out how hot the external temp of the engine is. Feel your radiator and make sure it's hot also, if not then your problem could be back at the thermostat.

 

[awd2gsx82]

i just had that problem with my 2g. it would heat up fast and cool down even faster. i figured out that the water/coolant froze in the block. not enough to blow the freeze plugs but enought to make it over heat cause it wasnt flowing properly. i let it sit in the heated garage for a couple of days and it fixed its self.

 

[sjm531]

theres definitely air in the system. a good way to test for a head gasket is a compression test and/or let the car warm up, and try to squeeze the coolant line. if its really hard, the cylinders are most likely pushing compression into the system but it does sound like theres just air in the system, probably from replacing the thermostat.

 

[Bubbs Malone]

I'm in agreement with air in the system, I had a similar problem overheating after replacing the motor with a used one. I let the car run a good ten or fifteen minutes with the cap off to make sure all of the air was out and filled it up. Then I bought a new radiator cap, it's worth it. I hope that's all it is.

 

[Hubbard 0]

Air in the system for sure or you're running low on coolant. When I had this issue, I would overheat at stoplights or drive-thrus after just a few seconds, but once moving again the temps went back to normal.

 

[Defiant]

DSMs won't hold air in their cooling systems.

You have a defective sender or its wiring, or a sticking thermostat.

 

[MrGriff750]

I also agree with the idea of air being in the system. I had an air pocket behind my thermostat on the block side and it would keep the coolant from opening it at idle. It was caused by a bad rubber coolant line that would leak occasionally.

 

[soulweaver]

Ok I got the car back from lucas smith and they said they fixed it. But go figure about 1 mile before I got to my house the temp started rising again. So I got it home and started to fill up the coolant and I was able to put a crap load of coolant in and there is still room. So I gotta go to the auto parts store after work today and get more then I will update this thread again. I did take it for a quick ride after I filled it up last night to my sisters house on the way there it got hot but not so hot I had to pull over. And, on the way back it got hot right away then it shot down to normal temp and stayed there. I do have a lot of electrical problems. All the wires on the thermostat have been cut and I put them back on my self but I don't know if there hooked up right. If anyone has a 90 laser can you tell me what color wire goes to what connection. I think I have it right caz the car starts and runs. Oh and another thing is my car has an Idle surge now since this problem started and the check engine light goes off and on.

 

[MrGriff750]

One thing i would suggest is every time before you drive top off the coolant and make sure the reserve is full, eventually you should be able to get out any air pockets, if that is an issue.

 

[Defiant]

The engines used in DSMs have no point higher that the thermostat housing in which they can hold an air pocket.

I suspect your head gasket, although with your wiring bazootied (nice to keep that secret for the first half of the thread), I wonder how you figure you're overheating at all.

 

[soulweaver]

The engines used in DSMs have no point higher that the thermostat housing in which they can hold an air pocket.

I suspect your head gasket, although with your wiring bazootied (nice to keep that secret for the first half of the thread), I wonder how you figure you're overheating at all.

The coolant temp sensor and the temp gauge are all wired correctly it's just the air conditioner sensor on the thermostat that is all bazootied. But now the car wont start and I'm gonna make a new thread about that and then we can get back to this one.