-.- Another Overheating / No heat Thread

Travis2000LS

Travis2000LS

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So.. Hey guys.. I havent been on much but anyways here is the deal. Ive done some searching and still no cure. Ive Tried replacing my MUCH needed to be replaced Thermostat Housing and bypass tube thinking that would be the source of my Overheating, Well it stopped the leak thats for sure but as for the overheating.. It started again last night. So I was like OH I just need to air bleed a few times and thatll fix her.. Well nope.. I spent a hour air bleeding still no heat at idle and overheating after about 5 miles now.. Ive done replaced the Hydo fan pump actuator which helped alot about 5 months ago. We did a Pressure test on the system about 3 months ago held good pressure giving me no reason to believe the degas bottle is the cause. So I HAVE NO CLUE! All I can think it maybe a clogged heater core would be my cause to this dreaded no heat but I couldnt see how a clogged heater core would cause Overheating? Or could it

Anyways let me know your thoughts. ill post some pics of the new parts on the LS.

THANKS!

Also I couldnt find a guide or write up on how to exactly flush the HEater core on the LS, is it a big job? If so more info on that aswell! Thanks

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Valve cover was off because Also changed the secondary timing chain ^^ it was stretched in like 4 links
 
No heat at idle only would be failure of the aux pump.

No heat anytime may be the DCCV, assuming that all air was bled out. When you did the bleeding, did you get a steady stream of water out at the last step?

I think that both heater cores being clogged is very unlikely. Has the heat ever worked since you've owned the car?

If you did get a steady stream of water out before, but can get more air out when re-bleeding, you still have one or more leaks somewhere.
 
I didnt get anymore air out. I get heat when you actually drive the car and keep RPMS up but only while moving. if the car is sitting still and is in park or neutral and rev it then still no heat.. what is the aux pump? and yes I did get a steady steam and i havent lost coolant
 
Travis2000LS said:
I didnt get anymore air out. I get heat when you actually drive the car and keep RPMS up but only while moving. if the car is sitting still and is in park or neutral and rev it then still no heat.. what is the aux pump? and yes I did get a steady steam and i havent lost coolant
Click to expand...

The aux pump is needed to provide coolant flow through the heater cores at engine idle and low RPM. It's mounted above or below the DCCV, at the right side of the radiator. It sounds like yours is bad. I think that you can just replace the brushes on the motor if this is the problem, but you are probably better off to replace the whole thing.

On to the overheating...

Does it only overheat at low speeds or while stopped? Or does it also overheat while traveling at over 45 MPH?
 
And in my case, it was actually the control from the DCCV was never turning on the pump. So it's worth some investigation.

**note: I'm an idiot. I meant the DATC climate control, not the DCCV solenoids.
 
oddball said:
And in my case, it was actually the control from the DCCV was never turning on the pump. So it's worth some investigation.
Click to expand...

I think that you mean the control from the DATC.
 
Yesterday we tested the aux pump it workable but for some reason something isn't telling the pump to turn on. We have to jump it to get it to work . As for the heat we think we fixed it. We got out a big price of plastic from the heater core . So we are thinking the radiator is clogged so I ordered that and a new upper radiator hose . And to oddball what did you have to replace in order to make the pump come on ?? You think this would be my problem ?
 
Travis2000LS said:
Yesterday we tested the aux pump it workable but for some reason something isn't telling the pump to turn on. We have to jump it to get it to work . As for the heat we think we fixed it. We got out a big price of plastic from the heater core . So we are thinking the radiator is clogged so I ordered that and a new upper radiator hose . And to oddball what did you have to replace in order to make the pump come on ?? You think this would be my problem ?
Click to expand...

The DATC controls the aux pump. Before condemning it, you should check the fuse for the pump and the wiring from the DATC to the pump. (DATC = the climate control module with the display and buttons.)
If the fuse is blown and blows again, it could be that you have a shorted DCCV.

Also, you should run the DATC self diagnostics and see what codes you get back.
 
Oh good lord, yes, DATC. Sorry. Geeeze.
That's what I get for posting while on the airplane ride back from a conference.

In my case, the DATC did not post any codes. I got another '02 unit from eBay, and it had the same problem. I grabbed an '00 circuit board from a local yard and that one finally worked. I guess it's a (somewhat) common issue. When I have time (har har) I intended to trace the board and see if this is a replaceable driver.
 
So this datc problem could cause over heating ?? Not just at idle . And I appreciate all yalls help btw
 
Travis2000LS said:
Maybe the rad is clogged then ??
Click to expand...

So, generally speaking cooling problems come down to insufficient coolant flow and/or insufficient air flow.

Coolant flow:

1. Insufficient because of steam created in the system because of leaks preventing pressurization of the system. - I think you've checked this.
2. Insufficient because of trapped air in the system because it wasn't bled after work done, or because of leaks. - I think you've checked this too.
3. Insufficient because of a faulty thermostat.
4. Insufficient because of a faulty water pump.
5. Insufficient because of a clogged radiator.

Has stop leak ever been used?

Air flow:

1. Insufficient because of faulty hydraulic fan system.
1a. Contaminated fluid.
1b. Bad pump.
1c. Bad control (solenoid) valve.
1d. Bad fan motor.
1e. Leaking hose or connection.

2. Insufficient because of dirt/trash clogging the radiator fins or the AC condenser.


Air flow problems (especially if fan caused) tend to show up much more a low speeds and idle.
Water flow problems often show more at high load (driving up hill, ...).
 
One more thing.
It sounds like you haven't changed your degas bottle. Maybe you should. It might pass a pressure test if it only has minor cracks. Also, there's a metal tube inside the bottle. If it falls loose, the bottle will let air instead of coolant back into the system each time it cools down.
 
I am having a similar issue. I repaired the leaking gasket at the base of my t-stat housing (and joegr I found out the torque spec from jag dealer is 9nm which i think the LS plastic housing is the same and for those interested the torque matters).

I have little heat at idle. 1500 rpm or over melts your face off. I checked the aux pump hose going to dccv, it was getting warm (this was just after startup last night.)

I will add that I did bleed the system properly but the air did get cool after letting off the throttle during the rev portion, but the instructions dont say what to do if no hot air comes out during idle. I have too much coolant in the system, and im not sute how to get it out since rebleeding would require filling again and probably land me right back where i am
 
The excess coolant will vent out of the degas cap as needed.
Can you feel or hear the aux pump running?
 
If you have heat at high revs and none at idle, then it's almost certainly that the aux pump isn't running. That can be caused by:
1) bad wiring/connectors/fuse
2) failed/siezed pump
3) DATC not commanding the pump to turn on
 
I've been wondering why I have no heat at idle....thanks guys for the insight....time to go hunting for the cause.
 
Hoping somebody can help before parts stores closer....wife said car was smoking when she pulled in driveway today. I pop the hood and coolant is everywhere on rear of engine. Can't tell where from or get it to leak again. Probably because of no pressure? Anyway, roughly middle of engine, just the rear, NOT the degas.
 
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