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Greasemonkey51
06-28-2013, 08:10 PM
Like the title states been having issues with this POS car over heating. I thought I had it fixed when I found a tiny pin hole on the recovery tank. Changed it out still likes to over heat. I'am thinking its the fans I never seen or heard them in the high speed only the low. Is there any way to check them out with out spending any money.(money is really tight)to see if their bad or not. Another ? which fan is for the ac and which one is for cooling. Little note Ac does not work so I cant even turn that on to see if they work on the high side. aslong has the car is moving It seems to be ok only when your sitting at lights it seem to rise in temperature. Also is the thermostat a pain to change never did one in these damn ga"s Thanks for any help anybody can give me on this issue..

AaronGTR
06-28-2013, 08:27 PM
The thermostat is easy to change. First question is, what temp are you actually seeing? We get a lot of people coming on here saying their car is overheating and it's just fine. It's normal for them to run anywhere from 200-220 degrees. The t-stat doesn't open until 195 and the high speed fans don't kick on until 230. Low speed fans kick on lower than that (218 I think, don't remember) or they kick on automatically if the A/C is on. There is no separate fan for A/C and cooling. Both fans run as a pair, at either low or high speed.

Greasemonkey51
06-28-2013, 08:43 PM
Almost half way to the hot side but its pushing out coolant and always have to add some almost every day. The oil is clean (no milky gunk) the gauge wont go down till shes(wifes car) moving down the road again. The coolant light comes on all the time. The tank is brand new installed it last week (Friday) the light goes off again when I top it off. I had this car for like 6yrs now and never had trouble with it over heating before. So I know this is a new issue with it. Just don't know where to start. About the thermostat do you have to take the cross over pipe off or no?

AaronGTR
06-28-2013, 10:26 PM
Nope, you can get the coolant pipe off that houses the T-stat without removing any of the exhaust.

If the coolant is boiling it could overheat. That could be the cause of low system pressure which could also be the cause of coolant venting and the system coolant level getting low. Usually caused by a bad pressure cap on the coolant overflow tank. Have you tried replacing that yet? It's a common problem with those, or the tank itself getting warped and not sealing, when they get old. Then they won't hold pressure like they should and the coolant boils at a lower temp.

Another possible cause is a bad head gasket. Something they go bad between the sealing ring around the cylinder which allows some compression to escape and pressurize the cooling system. You wouldn't see coolant in the oil, and you won't always see it burning coolant or overheating drastically if it's a small leak, but it will be enough to make the system vent and overheat slowly.

Try pulling the spark plugs and checking them to see if they are fouled. Here's a handy plug reading guide. http://www.motorcycleinfo.co.uk/resources/6795/assets/images/FAQs/electrics/check_spark_plug_condition.jpg You can find similar ones all over the internet. A bad looking plug on one cylinder could be a sign of trouble. You can get a compression and leak down test performed too. That will tell you if there is a problem with the head gasket, valves, or piston rings.

If none of that turns up anything, it could be junk built up in the system and needing a complete cooling system flush, or it could be a bad thermostat, or the fans not working properly.

I'd try replacing the t-stat and the pressure cap first as they are the cheapest and easiest, and also very common failures. Once they are replaced, at least you can rule them out if the problem persists.


edit: one other thing. Check and make sure you don't have any leaks anywhere else. Make sure there are no puddles under the car. No fluid around the radiator or heater hose connections. And nothing coming out the weep hole behind the water pump pulley (a sign the pump is going bad).

Greasemonkey51
06-29-2013, 06:50 AM
Nope, you can get the coolant pipe off that houses the T-stat without removing any of the exhaust.

If the coolant is boiling it could overheat. That could be the cause of low system pressure which could also be the cause of coolant venting and the system coolant level getting low. Usually caused by a bad pressure cap on the coolant overflow tank. Have you tried replacing that yet? It's a common problem with those, or the tank itself getting warped and not sealing, when they get old. Then they won't hold pressure like they should and the coolant boils at a lower temp.

Another possible cause is a bad head gasket. Something they go bad between the sealing ring around the cylinder which allows some compression to escape and pressurize the cooling system. You wouldn't see coolant in the oil, and you won't always see it burning coolant or overheating drastically if it's a small leak, but it will be enough to make the system vent and overheat slowly.

Try pulling the spark plugs and checking them to see if they are fouled. Here's a handy plug reading guide. http://www.motorcycleinfo.co.uk/resources/6795/assets/images/FAQs/electrics/check_spark_plug_condition.jpg You can find similar ones all over the internet. A bad looking plug on one cylinder could be a sign of trouble. You can get a compression and leak down test performed too. That will tell you if there is a problem with the head gasket, valves, or piston rings.

If none of that turns up anything, it could be junk built up in the system and needing a complete cooling system flush, or it could be a bad thermostat, or the fans not working properly.

I'd try replacing the t-stat and the pressure cap first as they are the cheapest and easiest, and also very common failures. Once they are replaced, at least you can rule them out if the problem persists.


edit: one other thing. Check and make sure you don't have any leaks anywhere else. Make sure there are no puddles under the car. No fluid around the radiator or heater hose connections. And nothing coming out the weep hole behind the water pump pulley (a sign the pump is going bad).

As I stated the tank(with new cap) is less then a week old I just put plugs in about the sametime this started they all checked out good nice and clean for being old ones. Theres no leaks any where else (checked and re checked). I guess I'll change the t-stat first and see if that help. thanks for the help..

AaronGTR
06-29-2013, 07:49 AM
As I stated the tank(with new cap) is less then a week old ...


well actually you said you replaced the tank. You didn't say anything about the pressure cap, and the aftermarket replacements don't always come with one so... ;)


but yeah, I'd try replacing the t-stat first, then get a compression and leak down test done if that doesn't fix it.

[ChaosweaveR]
06-29-2013, 11:09 AM
After changing the thermostat, bleed the air out of the system. The coolant bleeder is that hard line that runs across the front valve cover with the nut over on the right. What I've done is let the car run, crack open that nut and little by little let coolant come out until there's no more air bubbles.

Greasemonkey51
06-29-2013, 11:43 AM
Ok thx guys I'll give that a try and see what happens.

Starglow
06-29-2013, 12:32 PM
Which engine do you have...2.4 or 3400? I don't see that listed in your profile.
I leave the bleeder screw cracked open while refilling the coolant after a complete drain and you can hear the air being purged out through the bleeder screw.

Bleeding the cooling system is very important on these cars so you don't have any air pockets in the system. You can test the fan operation manually by jumpering the relay's inside the fuse box and I can tell you how to do that if necessary but I'll have to pull it from my notes, so let me know.

The other thing you need to know is if and when the fans are coming on if you really want to debug this thing. Let it sit and run idle with the hood down and listen for the fans to come on around 230 degrees...either they do or they don't. The fans are also controlled by relays inside the PCM which could be an issue if the PCM went bad.

Not so simple after all eh? Lot's of things to check. 8-)

Greasemonkey51
06-29-2013, 01:00 PM
Which engine do you have...2.4 or 3400? I don't see that listed in your profile.
I leave the bleeder screw cracked open while refilling the coolant after a complete drain and you can hear the air being purged out through the bleeder screw.

Bleeding the cooling system is very important on these cars so you don't have any air pockets in the system. You can test the fan operation manually by jumpering the relay's inside the fuse box and I can tell you how to do that if necessary but I'll have to pull it from my notes, so let me know.

The other thing you need to know is if and when the fans are coming on if you really want to debug this thing. Let it sit and run idle with the hood down and listen for the fans to come on around 230 degrees...either they do or they don't. The fans are also controlled by relays inside the PCM which could be an issue if the PCM went bad.

Not so simple after all eh? Lot's of things to check. 8-)

Sorry forgot to mention that in my profile I got the 3400. For the hearing of the fans I never heard them run ever. I did see them run once in slow speed that's it I just happen to open the hood and they were running kinda slow to me (not like other fans I seen or heard running). Back before this started I recall when the temp would start to climb after a couple of mins at a light it would drop back down. Still never heard the fans run but the temp would drop indicating they were working. So if you could dig them from your notes I would greatly appreciate it. And thx again

[ChaosweaveR]
06-29-2013, 01:12 PM
My GAGT did that in traffic, but never went past 220*F. I noticed it did that less when you bled the air out of the system. Air bubbles can prevent the the thermostat opening and closing at the temps it's supposed to.

AaronGTR
06-29-2013, 04:22 PM
Sorry forgot to mention that in my profile I got the 3400. For the hearing of the fans I never heard them run ever. I did see them run once in slow speed that's it I just happen to open the hood and they were running kinda slow to me (not like other fans I seen or heard running). Back before this started I recall when the temp would start to climb after a couple of mins at a light it would drop back down. Still never heard the fans run but the temp would drop indicating they were working. So if you could dig them from your notes I would greatly appreciate it. And thx again


Yeah, you won't hear them when they are running low speed. Most people can't even hear them when they are running high speed unless the get out and open the hood. I have a manual switch installed in my car that allows me to run them at higher power than the normal high speed, and that is the only time I can hear them inside the car. I only use them to cool the car off in staging lanes at the drag strip.

I looked up the numbers. Stock programming, the low speed fans don't even turn on until 222.8 degrees F (106 celcius) and turn off when the temp drops back to 217.4 (103 C). The high speed fans don't come on until 231.8 (111 C) and off at 226.4 (108 C).

Keep in mind the stock T-stat is 195 degrees, which means it starts opening basically at 190 and should be fully open at 200. Even with it open though, and even with the fans running, the coolant will only stay as cool as the capacity of the system to shed heat. If it's hot outside and your car is standing still, the temp will go up a little. The radiator is only so big and the fans only move so much air. Basically if your temp isn't going over 230, then nothing is wrong.

Coolant should be changed every 5 years or 100k miles though, so if it's never been done on your car, I'd do that and change the t-stat anyway for good measure. Refill the system and bleed the air out. As long as the temps stay in the same range you are fine.

Starglow
06-30-2013, 12:58 AM
There are three relays in the under hood fuse box that control the fan operation. The relays are Fan #1, Fan #2, and the Mode Control relay. Refer to the fuse box lid diagram for relay location identification.

You will need to make up a jumper wire and a ground wire to run this test. Note: Run the tests with the engine off, but the ignition key must be in the on position.

Both fans operate through fan relay #1 in serial mode and the mode control relay during low speed operation. The mode control relay toggle switches to route power through fan relay #1 and #2 for high speed fan operation.

Test Mode:

Slow speed: Remove Fan relay #1 and jumper terminals #30 to #87 on the relay fuse block location to operate both fans at slow speed.

High speed: With Fan relay #1 removed and terminal #30 to #87 jumper wire still in place with fans running at low speed, supply a ground connection to mode control relay terminal #86 which is the same terminal grounded by the PCM (with the mode control relay still in place but pulled up slightly) and the fans will switch from low speed to high speed.

You can find the terminal numbers on the relays. The relays themselves can be tested as well out of the car. Apply 12V to the hot side terminals with an ohm meter connected to the output switching side terminals which should have continuity only when 12V is applied on the hot side. You should hear the relay clicking inside as well. I used a bench 12V DC power supply for the relay testing.

Here's a schematic that might help as well. It can be found in the back of the Haynes manual.

http://i10.photobucket.com/albums/a138/Starglow/3500%20Engine%20Swap/heater-acwiringdiag.jpg (http://s10.photobucket.com/user/Starglow/media/3500%20Engine%20Swap/heater-acwiringdiag.jpg.html)

Greasemonkey51
06-30-2013, 09:32 AM
Star thx for the info, now the fun part..

Starglow
06-30-2013, 12:52 PM
If the fans work fine during the tests and the relays are good, then it could be a PCM issue. However, the coolant temp sensor data is also used by the PCM for many things. So if the temp sensor is suspect or isn't working correctly then the PCM may not get a signal to turn on the fans.

Good luck.....! :)

Greasemonkey51
07-03-2013, 04:11 PM
Alright got time to check this thing out I jumped the low side and it came on (fans) now I pulled up but not remove the mode relay and tried grounding the 86 terminal on the high speed side and I got a big ass spark that's it what did I do wrong and why did it spark. Kinda lost the on the pcm relay inless that's the mode one. And yes I jumped when it sparked..Other words what the hell does PCM stand for

blckgagt
07-03-2013, 04:43 PM
Alright got time to check this thing out I jumped the low side and it came on (fans) now I pulled up but not remove the mode relay and tried grounding the 86 terminal on the high speed side and I got a big ass spark that's it what did I do wrong and why did it spark. Kinda lost the on the pcm relay inless that's the mode one. And yes I jumped when it sparked..Other words what the hell does PCM stand for

Powertrain control module. Often referred to as an ECU(Engine Control Unit) or ECM (Engine control module)

Greasemonkey51
07-03-2013, 05:53 PM
Powertrain control module. Often referred to as an ECU(Engine Control Unit) or ECM (Engine control module)

ohh ok duh me thx

Greasemonkey51
07-04-2013, 06:56 PM
Umm help don't have a clue what I did wrong.