engine overheating of my pontiac transport 1990

[vijayan]

hey my pontiac transport 1990 engine seems to be overheating while in motion can anyone tell me how to fix this problem

[LMP]

THe easier first fix/test is simply to REMOVE the thermostat. IN your country, I do don't hink this will run the car too cold.....and at least it will tell if this is the cause...I would be glad it solves the problem so simply and the story would end there. Do not change expensive parts like radiator or water pump as some use to try..to no avail....you can also try to flush the radiator....

HOwever, with the 3.1/3.4 engine, there is a very well known and somber trend of blown head gaskets. Look for these symptoms:
- irregular heat flow from the heater....of course you do not need that where you are..but try it anyway with the TEMP lever at max , fan at 3rd speed (do not use full speed) and no A/C
- erratic temperature indicator: goes up and down
- steaming
- emptying of coolant reserve tank: have to top off regularly
Report findings

[vijayan]

i did all this but still the temprature goes high in motion and wat do you mean by emptying the coolant reserve tank

[LMP]

Originally Posted by vijayan

emptying the coolant reserve tank

WEll I should have said the level in the radiator goes lower and lower...: it "burns" coolant!
If it does not steam out, then it will progressively siphon the reserve tank down...and you'll have to add coolant from time to time. OR it will simply steam the coolant out...and similarly, you will have to top off.

[vijayan]

hey thanks for replying back and all... my pontiac still overheats while in motion i have bought this recently from a man when i drove it to my house it alwayas used turn off and shake rapidly when i stop the car in the traffic light and when i used to start the car in the garage the side wall gets extremly black from the exhaust and once when i checked the oil the oil seemed to be a liitle dark and i don't know how to say it . it din't seem to be like good oil so i took it to a
friend of mine's garage to fix all of the problem he changed the oil changed the brake pad and had some electrical work and some othe work witch i have forgotten but after all this the car now does not get off does not shake and the smoke comming from the exhaust is not that black anymore and i guess that,s all after a week the car started to shake a little when the car was in drive and was not in motion and the car now started to get off after starting it and going slow and the temprature goes high and the car is not smooth anymore does the above reason's help please reply as soon as you can

[LMP]

I do not see a connection between the black smoke and overheating. To me that sounds alike 2 different problems. I suppose the engine runned rich for some reason ..and there might be many - and that issue was apparently corrected by you friend: it could have been a disconnected or failed sensor, or blocked thrttle body injector....who knows...he might be able to tell what he did.
As you did not mention any white goo from dumping the engine oil, I think at that time there was no severe coolant leak to a cylinder...
AS for the "shaking", (with no black smoke), I think it is spark related. I had a lot of shaking 2 years ago, making the car almost unserviceable, and I changed the spark plug wires (13 year old) and all went OK after that. But ONE failed spark plug...for any reason...can cause a lot of shaking.

WHen you say "the car started to get off..." you mean it idles at high RPMafter starting then slows down after it gets warmer..right ? My son's GM 3.4 DOHC (Z34) does the same thing..and this problem comes quite often on the web...it was suggested a leak of the intake manifold would do that but no one came back saying clearly they corrected the problem and by what means. WHen winter's gone, I'll "trick" the temp sensor to make the computer believe the engine is warm and see what happens...

Bottom line, I have no other cues about your overheating. TO test the blown gasket theory, I inject compressed air into each cylinder, one at a time, using the spark plug hole, and turning the engine so both valves are closed on the test cylinder. THis is easy on the front three plugs....and if it does not reveal anything, doing it on the rear is harder....
A failed gasket will let air seep through the cooling system and bubble out at the radiator cap if you fill it up to the top.

[vijayan]

today my cars engine temprature came above 230 and when i start the car i just accelerated the car in neutral and when i put it to drive the car goes off it gets off even at low temp

[LMP]

Yes that is what I had understood.
THis high idle problem is separate from the overheating...my son'S car has the high idle, as several others have also told on this and other forums, but do not have overheating problems.
I have not managed to solve that problem (high idle) from the root....have checked the idle air control valve..to no avail. I think something is screwed up in sensors somewhere and the computer gives false commands to the idle controller. a leak at intake manifold is a possible explanation as some have suggested but no time to look into this at this time.
WHat I will try soon to go around the problem is this:
RUn car until warm and engine idles normamlly.
Keep engine running, open hood and disconnect idle air control valve in it "relaxed" position.
Stop engine.
My expectation is at next start, the engine will idle slowly...may be too slow and will require driver action for a few seconds or minutes....will report the result.

I have noticed that when the ignition key is turned to OFF with the IDLE AIR CONTROL valve connected, that it resets to starting position right at turn off...

One question: is your Check Engine Light ON? If so, read the codes.
www.avigex.ca/xport/readingcodes.jpg

[vijayan]

my car is a pontiac transport 1990 it doen,t have any computer inside it so there's no codes or anything being shown if it is there please let me know and wat do mean by the engine light i could"nt locate one i fond one when i opened the hood it was to the left it din't work and the car stopped has stopped getting of now it's only the overheating problem

[LMP]

the plug for the computer is there under dash, left side

CHeck engine light (CEL) is an orange kind of engine icon showing on instrument panel or a label saying SERVICE ENGINE SOON. When you turn the key ON, it will light up with all other indicators, then shut off when engine is started...or keep showing if a code is stored. HOwever some codes may be stored even if the CEL if OFF as some codes are non critical, or some past malfunction that trigged a code before is no longer detected but the code stays there.
NOtice that if battery is disconnected for a few minutes, all codes are erased.

[vijayan]

i have checked under the dash it is there wat you have to plug in that ..and i forgot to mention to you when i put my car to on a bright orange light gets on it,s not the low fuel warning is that the engine light

[LMP]

Originally Posted by vijayan

i have checked under the dash it is there wat you have to plug in that ..and i forgot to mention to you when i put my car to on a bright orange light gets on ... is that the engine light

...the light has the appearance of a little engine or says Service Engine SOON,
ANyway. connect a little wire from A to B , turn key on and count the blinks of the Check Engine LIght.as described here:
www.avigex.ca/xport/readingcodes.jpg

[vijayan]

hey anyone out there

[vijayan]

wat does the yello light mean it is under the speedometer its gets for some time and the go off

[LMP]

NOt sure which one..anything written on it? ..there might have been a few variations over the years.
If it turns OFF, whetever it is, it means a normal condition...so maybe you have no recent codes stored, but there might be some anyway unless the battery was disconnected for a few mnutes.
......in any case, do the flash test as I explained above.If one light flashes, you will not miss it.....