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89 Iroc Coolant Temp?

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mjrad

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Discussion starter · #1 · (Edited)
Just wondering... What should the coolant temperature read? Mine reads up to 260 on the instrument panel...mine is reading 240 after 1/2 an hour?
Also one of the fans is not working...would this cause it to overheat?
Mark:confused:
 
#2 ·
Normally, temp is around 210*F-220*F, better emissions control. One fan is operated by a thermal switch, maybe comes on at 235*F(?).

The other fan, and both fans, should come on with A/C or DEF selected and the supporting relay is controlled by the PCM. So, if this fan is not working, bad relay contacts, blown power supply fuse/fusible link, or bad PCM driver for the relay, or bad PCM coolant temp sensor.

If bad PCM coolant temp sensor, two-wire sensor, then engine will not fast idle when engine is cold.
 
#3 ·
My 88 TPI car runs about 210* with everything stock. The temp guages on these are known for accuracy issues. I still have the factory guage, but I know many people who put a second temp guage to make sure. To see if the fan is the issue, you could hard wire it to a switch and turn it on once temp gets around 200. I also know people who do this in case one of the sensors fail - even though if a failure occurs, it is supposed to put the fans on at all times - not keep them off. If it's not coming on, I would think it woudl be a ground or wiring issue. Check the thermal switch wire on the passenger side engine.

-Dan
 
Discussion starter · #4 ·
OK
check the connections ,nothing is loose
However when i put the ac on there is nothing but hot air in all the selections.
this being the first day i take it out of town at least half hour ride,
i get high temps at lights and stop and go
but when im cruising the temp gos down to around 120
also when i started it up after cooling down for 2 hours
i noticed OIL inbetween the injectors on the passenger side
and high idle when start up with alot of white smoke from the tail pipes,
this was not the case when i returned from my trip
also the one fan will not go on with the heater or defrost,
instead the other one cuts out as well
wow did i bye a lemon:mad:other than that it still sounds good:confused:
but also doesent seem to be kicking in like it should
thanks
mark
 
#5 ·
Select A/C and hot air, maybe compressor is not kicking on due to low freon in system, maybe, or loss of battery power to compressor/A/C system, however, blower works, so that's good. I suspect low gas in A/C. Look for a leak with leak detectant.

Low temps while cruising, thermostat is stuck open. If you open the coolant system, might as well re-hose it, flush the block, clean the radiator, if not replace it, re-belt it, and new coolant, 50/50 mix. Be sure to purge the air out, may take several overnight cooldowns to accomplish. Make sure reservior is clean and no leaks, replace radiator cap.

Oil between injectors could be coming from center intake bolts as they go into crankcase. PVC valve and hose and nipple may be plugged or not working. Also, could be too much blowby from worn rings, excessive crankcase pressure shoving out oil through bolt threads. Or, leaky valve cover gaskets.

High idle when cold is good. White smoke at startup means vlave stem seals are worn, heads may need reworking, for a later time.

Fans not working could be one side of fan relay not having battery power due to blown fusible link at starter solenoid post, or blown fuse. The one fan being on when A/C is not selected and turning off when A/C is selected means one side of relay coil has no battery voltage. The other wire of the relay coil is the control line from PCM. When PCM calls for fan relay to energize, the PCM control line goes low. If coil has battery voltage on the other coil wire, relay energizes and fan comes on. But, just opposite is happening, so no battery power to one side of relay coil.

The other fan not coming on could be due to a broken thermo switch, either on the pass head, or next to the thermostat housing. Or once again, no battery power to one side of relay coil.

Get a Haynes manual for the car model and read up. Take it to bed and through osmosis, the info will drain right into the brain......LOL.

Lemon? You pay for what you get.....a used car.
 
#6 ·
I hope you meant cool down 220*:) If not, that's quite a change. Sounds like you need a compression check and maybe a leak down test. This will tell you where the smoke is coming from and most likely the oil as well. If it's a busted head gasket or manifold gasket, the smoke could also be coolant - it's hard to tell blue from white smoke in many cases. Usually on statup it is oil leaking past, but mine did it with coolant as well. You could pull the plugs and see if any look extra clean - like they been steamed cleaned from antifreeze leak. You need to pull the plugs anyway for the compression test. You could also keep an eye on your radiator fluid level - it only takes a tiny bit of liquid in the cylinders to make it smoke, so it may not drop much over a week or 2. It's a TPI car, so removing all the stuff to put new top end gaskets is a real PITA. I did mine last winter with new heads and headers. I had both problems - the usual leaky seals that 305s (it's a convertible - no 350s) seem to get as soon as the warranty ran out, and a blown head gasket.

-Dan
 
Discussion starter · #8 ·
ok just got done replacing the motor for the fan on the passenger side ,
it still does not want to come on ,hot or cold air ,
for $26 now i have a extra fan
should i go ahead and order pcm because i have no idea how to check for voltage or fuse link ? i check the fuse box and they all look good i dident pull any out or anything just looked to see if any were burnt out
i also check all connections unpluged everything and pluged everything back in one by one ?
i also changed my tstat ,i have to get another seal ?
geuss it moved ,theres a little seepage but than again i started it right when i was done i figured it shouldent matter
i also notice that when the temp gets to 240 the driver side fan does come on and the temp goes right down ?
also on each start up the rpm is 1500
but if i put in anything but park n nuatral its at 800
after worm up its like a 1000-900,
does that sound right?
also i picked up a code reader for the engine light on
and it still is not reading anything but 12 and the service engine soon light still wont go away ?
i also have no freeon ,i took that tire thing off and air comes out?
i have no idea why ?
mark
 
#10 ·
It's in the passenger side head. This article explains the operational nicely http://www.thirdgen.org/electric_coolant_fan_spec_mod_dual.

I wouldn't replace the ECM - usually 1 thing doesn't break - they tend to work or not work. If the only trouble you have is the fan, that's not bad:)

-Dan
 
#11 ·
Check for power at the corresponding fan relay. Should be two big wires, one shold have battery coltage on it, the other large wire will go to the fan motor. Same relay socket, two smaller wires, one should have battery voltage, the other wire will go back to the ECM or one of the two wires is connected to the A/C switch and the other wire is ground. Either way, the relay coil has to have battery voltage on one side and a low voltage or ground to energize to close the contacts to turn on the fan motor.

Have you gotten the Haynes manual yet?
 
#14 ·
Alldata appears to be good info. Better than Haynes. I go to a local repair shop and get my info from Mitchell Repair CD. Shop doesn't charge me anything to print out, but I buy a pizza for them.

I was suggesting Haynes because its better than nothing.
 
#15 ·
allldtat seems to give info in much more depth, for example, rather than a schematic showing a pile of grounds, alldata labels them as a number, and then tells you where that ground trunk number is located...ie: ground trunk 1002 is bolted to drivers rear cyl head...(just an example)...i`ve had problems with the connections at the fan plug alot...look there for corrosion...also, your scanner, does it have functionality tests???it may test the fan relays for you...my snap-on does, but its a shop level scanner...i dont know if yours will...there is a coolant temp sensor, and a guage sensor on your car...could be that the car isnt overheating at all...look at the data stream on your scanner...the fans wont even come on until the car hits 224-227 deg...the guage sensor could be inaccurate, and only reading hot...you definately want ti get it running cool (at operating temp) though...i think you can subscribe to alldata online for your specific car for like 25 bux...
 
Discussion starter · #16 ·
ok the first day i bruoght this car it dident make it home
it sat in the garage for the weekend and had the fuel filter changed,
it drove home fine , next day same thing bogging down and engine goes
silent if too much gas,this time i bring it to another garage ,
they changed the maf ,the problem still was there so they checket the cat
it was fine , changed the tps and the problem was gone for a week
that gave me time to realize cooling era ,nowthat problem is fixed
now all over again it shut off on me on the highway completly silent
intill i totally let off the gas ,and than its like it gos on and off
on its own if i touch the gas a littel it cuts off but comes back on
the ignition stays on ,its just the engine that gos off
my guess from the beginning is the fuel pump
how can i be sure and if thats not it ,i get nothing on the scanner
but still have a service engine soon light .
thanks mark
 
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mjrad
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