95 Lumina APV 3800 Overheating Issues

[Ycb]

Hello all, every since summer started I've noticed my engine temperature increasing for obvious reasons. But the temperature significantly increases when my car is idling i.e in heavy traffic or just normal idling. But as long as the car is moving and air is passing through the temperature is pretty much stable (about halfway).

I had this issue from before which has been resolved
http://www.automotiveforums.com/vbulletin/t438685.html

I have replaced the thermostat, repaired the water pump. The only thing now I can think of is that the radiator is not doing its job, because it is clogged or malfunctioned. The fan works and the only way I can reduce the engine temp is to crank the heating to full. So for example if it is say 30 degrees outside, in my cabin it would be about 36 degrees or more haha. I talked to another person about this, and they say to flush out the radiator.

Is it hard to remove the radiator?

Any help would be great!!

Thanks !!!

[LMP]

"Flushing" a radiator rarely solves such problem. MOst often very thin mineral deposits from hard make-up water impair heat transfer and this does not go with a "flush".
Make sure there is no external clogging at A/C radiator from vegetation . Also, make sure fans work specially if A/C is used at idle. I kind of understand the problem alleviates or disappears when running at highway speeds and this rules out engine problems.....

TO remove radiator requires detaching the dogbone at radiator and swing rearward. then, as the book says:
- remove forward lamp harness from fan frame and unplug fan connecetor
- remove fan attaching bolts
- remove fan and frame assembly
- remove hoodlatch (mark position to ease reinstallation)
- remove coolant hoses, transaxle coolant lines and radiator support bolts
- remove radiator.

[Ycb]

Thanks for the reply LMP. Also I forgot to mention that since I fixed my PCM ~2 years ago, my check engine light still comes on. I've noticed it comes on right when the temperature gauge reads just below 1/4 (assuming Cold = 0 and RED hot = 1).. There seems to be no issue with the engine, so it's been on since.

[Ycb]

OK, after more reading, and observing I've noticed that the fan on the inside of the radiator (the larger one one on the driver side) is not spinning. I pulled out the connection and measured the voltage and it gave ~14 volts when the A/C was turned on. With the A/C turned off the voltage was ~0.00x volts.

Is there anyway to test the fan? or do I need to pull it out and put 12volts through it?

[LMP]

If you can reach the plug as is, use wires to suit , feed 12V on fan side of the plug to test the fan. This figures as a rational explanation to our problem.

[Ycb]

Hey LMP, I tested the the fan with 12volts and it spins!?!?

so nothing is wrong with the fan. When the AC goes on it still produces voltage, yet the fan does not spin..

Is there a relay of some sort?

[LMP]

relays are here (next to right hand headlight cluster)
www.avigex.ca/xport/relays.jpg
NOw if you cna measure 12V reaching the plug with A/C on but when the fan is disconnected, this might indicate a fouled/corroded plug or bad relay contacts.... easy to measure 12V at no load, but the voltage drops down as soon as a load is applied....

[Ycb]

ugh... i checked the relays and they all seem to be working..

the fan relay is the only one with 5 pins...

LMP could u explain how to test for a
"this might indicate a fouled/corroded plug or bad relay contacts."

Thanks !!

[LMP]

Well sometimes connectors seem to make a connexion and do not because of corrosion or heat damage.
...this diagram www.avigex.ca/xport/fandiagram.jpg
shows only 4 relay contacts are active. ALso make sure you have checked for the right relay: the picture said the relays are not shown necessarily in proper sequence. IN fact, the only relay i diagrams that actually uses 5 contacts is the fuel pump relay.... www.avigex.ca/xport/fuelcontrol_iac.jpg

The relay can have a normally opened and a normally closed contact, but here only the normally opened is used...so you could swap relays for a test as relays that have only 4 contacts simply miss the normally closed contact that is not used here anyway.

If that does not change a thing, sInce you say the fan is OK and there seems to have 12v at the fan plug , I would disconnect the connector, then plug a pair of wire from the plug (feed side); activate A/C to check for voltage then if voltage is there, connect the wires to the fan side of the plug and the fan will either run or not...: if it runs, then it proves you have made a better contact and the plug is the culprit...

[Ycb]

I was thinking that that fan relay had 5 pins, because I searched Rockauto.com and it says that

1995 CHEVROLET LUMINA APV 3.8L 231cid V6 MFI (L) : Electrical-Switch & Relay : Fan Relay ACDELCO Part # 158719 More Info {5 PIN, MINI, BLACK #12193601}
RELAY,FAN CONT CODE 3601

And regarding the a bad plug, I have disconnected the fan plug, and run my own wires to the fan, but the fan did not run. The voltage during this was lowered though to about 10v, and I just assumed it was due to a poor connection I have made with the wires.

[Ycb]

I went to get the engine code read today, and it gave a code of DTC P1640.
They gave a print out of "possible errors" seems to be something with the Quad driver module (QDM).. Any ideas?

I found this link with google that has something to do with the fans and the DDM http://www.autozone.com/images/cds/g...3d800f1b77.gif



Update

So I was driving around tonight noticed vibrations in the car, and was kinda worried about what was going on. Seems the fan started to run, I noticed my engine temperature at a very good level. Only thing I could think of today that I did different was jiggled and checked the relay wires, got the ODB code read, filled a bit of premium the other day, and filled regular today??? haha

hopefully the fan will keep running, and I fixed a faulty connection somewhere.

Now what is this Quad driver module error? the problems...


Side question, would premium gas be better then regular for this van? or would it show no significant difference?

[LMP]

Quad driver is an electronic power driver that runs the relays on and off. If for some reason one of the relays makes a weird contact, the voltage at the driver will read erroneous and you will have that code which does not indicate a failed driver, but an unusual voltage condition at the driver, the cause of which can be anything . SO....there was probably a poor contact somewhere that you have indeed corrected unknowingly...ehh...il will probably come again....
And yes, the 5 contacts relays are used all across the board, and only relevant contacts are used.
...and I would not throw my money out using premium gas. The advantage is there only if you have the compression ratio that requires it and the advantage comes from the compression ratio, not from the gas "energy contents" that is same as regular: it is just the fact that in a high compression ratio engine, regular gas would ignite prematuraly causing knocking and, with computer cars, would induce an extremely retarded spark that would then impair power....premium gas is just able to withstand high compression without exploding by itself: it will still wait for the spark.

[Android_Gimpy6456]

Ok I have the same exact problem, When I bought my van it got hot when I sat at idle culprit...Fan not spinning. Fix: Relay for Fan After I replaced the relay the fan spun, but it didn't kick off while the van was running. Weird I had never heard of this proplem. The only way it would run was if I kept the defroster on but I can keep it on cool. Any ideas, and yes my CEL comes on EVERY time I start the van. Also my cluth on my A/C compresser wont engage and my A/C fan wont spin.

[Ycb]

Have you changed the thermostat?

Also what was the problem from the CEL

[LMP]

...(continued)..
YOur "quad driver" code was relevant with your problem: it could tell that at the time the fan relay was ordered to run, the condition of the circuit was not normal...like an open contact to the fan relay coil. It seems you have fixed that by jiggling with the wire bundles or plugging/unplugging the relays. Was the code cleared at time of reading? If not, Disconnect the battery (disconnect main wire with a red cover near brake booster on firewall) and turn light switch to ON to drain any residual charge for say 10 minutes to clear the codes,(well this worked with OBD1..not sure with '95 OBD1/2 or 2) this to see if they come again, and report.