Co-workers 2004 overheating

[streetglideok]

See if it is a code in the p0600 range or not. Those are the fault codes for PCM problems. Only way that will cause it to overheat is if the fan wont come on when it needs to though. Before I went and spent that kind of money for the PCM replacement, I would want to verify the power and grounds were all good for the module. Otherwise, you may cook the new one. Replacing that module may prove beyond what they can do at home, so they may want to prepare to take it to a shop.

 

[Xodius]

Their KJ is a 4 cylinder.

I left her a voicemail to find out about the code that is being thrown and to triple check some of the other things she has told me.

I did mention to them that it is possible one of the new relays was bad but she said her husband checked them and they all have the right current going through them.

Glad I am not the only one that thinks it is not the PCM. Hopefully they will figure this out.

 

[Xodius]

The codes are 480&481. It has a
Motorila PCM. Also I just found
Out it is a 3.7 not the 4 ****** like they told me before.


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[Xodius]

Would there be a loss in compression if the head is cracked or
Gasket bad?


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[streetglideok]

Ok, those are the two codes regarding low and high speed cooling fan relays. The codes could have set if they were taking out and installing the fan relays while the engine was running. I would clear the codes and see if they come back. Next thing I would do is verify, if I had to do it myself even, that, A)does the radiator fan come on when the a/c is turned on, and B) does the radiator fan come on when the engine temp gets high, and C) does this thing only overheat at idle, going down the hwy, or in slow moving traffic? They need to verify each of those things, again, to see where they stand. My guess is, they havent really done or checked all of what I said, its been inferred but not verified.

 

[streetglideok]

Would there be a loss in compression if the head is cracked or
Gasket bad?


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Not always. In severe cases yes, but in smaller leaks, not always due to the amount of cylinder pressure required to make the leak. Need to try a CO block test.

 

[Xodius]

The fan works with ac and it also kicks in when it gets hot/high temps. It seems to get hot when driving on both surface streets and idle. They have not taken it on the highway.

He did say that when he tested the old fan with a battery it was moving serious air but when he tested the new one installed it moved very little air which is why he thinks it is the PCM because that controls the fan speeds. That true? When the fan was out and he tested it there was a lot of air movement.

It just got out of warranty and the local dealership, which ever one they took it too said they would not do the recall on the PCM unless they determine it is in fact bad. They would not swap it just because it says too. Is it just me or it that a bit jacked up?

Is a CO test a compression test?


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[streetglideok]

CO test is a Carbonmonoxide test. http://www.autozone.com/autozone/ac...&fromString=search&itemIdentifier=391378_0_0_
Thats a link to one. Most parts stores carry them. The PCM doesnt control the fans, it only controls the relays that power the fans. Should be probably 3 wires on the fan, common ground, then a low speed, and a high speed. Pcm will energize one relay or the other, which works as a remote switch for it. When it does, the relay allows power to reach the fan, thats all. If the PCM can turn on the fan with the a/c turned on, and when it reaches the threshold to turn on the fan because of engine temp, we've concluded that the PCM has control of the fans, and is doing its part to control temps. If its still overheating, the PCM has nothing to do with it then. You're dealing with a different problem now. It isnt airflow, since the fans come on, and it overheats at idle, and it seems to overheat at idle, so either you have zero coolant circulation, or possibly a combustion chamber leak(combustion gasses leaking from cylinder into coolant jacket). When its warmed up but hasnt overheated, how well does the heat blow? Turn it on high, and see how hot it gets, and stays. If it can crank out plenty of hot air, and the engine temps are rising, coolant circulation isnt the issue. Scratch off the water pump. At that point, go to the parts store, get the tester I mentioned, and time to do the test. Want to make sure the coolant level is down a ways, as you dont want it to push coolant into the test bottle, it will give a false reading. Should have instructions with it, and will make more sense then.

 

[tjkj2002]

Generic block test instructions.............

http://www.blockchek.com/instructions.htm

Any color but blue and you got a leak.

Another possibility is bad wiring,maybe the wires from the relay to the fans got to hot and now have very high resistance which can acount for the slow fan speeds.Simple check with a DMM.

 

[Xodius]

iTunes for me.


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[streetglideok]

Whats the update on the friends jeep?

 

[Xodius]

Update, after work i talked to coworkers husband and he is still convinced it is the PCM. So he took it to a shop here in town that can pull the code and see if there is an issue with it and if there is they build a new one for him at $240. I am sure they will find something wrong with it just for the sale.
He kept asking me if it was the head or gasket why is there no film on/in the coolant. I just kept saying look these guys know their stuff and if they think it is that you should really
check it out. Then he goes on to say that he checked all the hoses an there were no blockages and they all looked good. He said even the old fluid look good that he dumped out of rad and I told him of course, I put my spare from my jeep in so your wife could get home. He just kept saying no no that is not it. I just laughed and told him to keep me posted. He said he would.


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[Banditsteve]

Just thinking outside the box for a minute. Does the thermostat actually open? I know you replaced it but that doesn't guarantee it works. Might be worthwhile taking it out and sticking it in a kettle to make sure it opens. An old kettle would be better unless you like the taste of cheap wine afterwards or the mrs is out? Just a thought. Same as everyone here has said, eliminate the obvious and easy first. Steve :smokin:

 

[Ry' N Jen]

I'm thinking that there is an obstruction somewhere in the cooling system.
Has the cooling system been flushed by a dealer?

 

[streetglideok]

Xodius, sometimes you cant tell some people anything. You tried, we tried, and if he chooses to not listen, then so be it. Its his money, just dont have pitty towards him if he finds out the hard way, that he is wrong. Only way some people learn, and even then, they usually dont, they just make guys like me richer

 

[Xodius]

Lol well they swapped out the PCM and still have issues. They have not driven enough for it to get overheated but the gauge goes past mid. This weekend they are going to try driving it and see what happens. I was also told from the wife, coworker, that her husband does not want her to tell me that we might be right. So he is going to try some snake oil, crack seal that you add to the rad. Should be interesting. I can hardly wait for Mondays update. Lol.


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[streetglideok]

Oh holy ****, not that stuff. That'll do a great job of stopping up the ol' radiator, and heatercore, and make a mess when it comes time to actually fix the problem. I feel for the tech that is going to have to straighten out that mess.

 

[Ry' N Jen]

Lol well they swapped out the PCM and still have issues. They have not driven enough for it to get overheated but the gauge goes past mid. This weekend they are going to try driving it and see what happens. I was also told from the wife, coworker, that her husband does not want her to tell me that we might be right. So he is going to try some snake oil, crack seal that you add to the rad. Should be interesting. I can hardly wait for Mondays update. Lol.


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You are just asking for additional problems with that crap!

 

[Xodius]

Monday update
No work done on it over the weekend. I was told they will be working on it today...maybe. Should be interesting. The coworker wants it fixed now and her husband says don't complain you still have a car to drive. They have about 4 car/vehicles not counting motorcycles in various stages of not working lol.


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[Okura_hubby]

Just thinking outside the box for a minute. Does the thermostat actually open? I know you replaced it but that doesn't guarantee it works. Might be worthwhile taking it out and sticking it in a kettle to make sure it opens. An old kettle would be better unless you like the taste of cheap wine afterwards or the mrs is out? Just a thought. Same as everyone here has said, eliminate the obvious and easy first. Steve :smokin:

i LIKE THIS CHOICE. Running hot I bet its the termostat.

To take it a step furter.. This is a temp fix/troubleshoot. And cost the cost of antifreeze.. I would take out the termostat. put back together (minus the termostat). does it still run hot? If so its not the termostat. If it runs cool then it was.. Then if not.. I would look at other things. Maybe water pump not performing well..