: Manifold or water pump causing overheating???



LukkaF
07-12-08, 08:56 PM
Can anyone help me with some advice please? I own a 2000 dhs which has about 112k on it - i love the car and have always taken good care of it service wise and had no problems. . .until now . .when i start the car it will heat up and just keep on heating up until its in the red (usually within 6-7 miles of driving from cold). at first i thought it was leaking coolant and that does seem to be the case but the dealer and my mechanic are telling me two different things . . dealer says i need to change the water pump and crossover (where they say the leak is) which is fairly nominal in cost .. but my mechanic who i and many friends do trust says the problem is actually from the manifold intake which is leaking the coolant and that i should take it to the dealer to fix because its too complicated for him - he said my pump and crossover are fine. . .i do not understand as even when the coolant is completely full the car still "overheats" . . or at least it says its overheating, i never really know because it does not feel hot or smell bad and on a couple occasions when this happened i had to get home and it was all the way in the red . .to the point the car would tell me to pull over, and then the computer even overrides something and you cant drive past 2000 rpms . . or a speed, cant quite tell what its doing but its meddling . . . . i thought maybe its just an electrical issue as the sensors have been the only thinf on the car that have been spotty in the past . .told me random things like check coolant and oil level when they have been fine. . i do know there is now a leak, but i am not sure from where? and why if its full is the car still saying its running hot?? does any of this make sense? the dealer and the mechanic are telling me such different things . . i dont want to sell the cadi! Help please!
Thanks!

Ranger
07-12-08, 09:20 PM
Crossover gaskets on post 2000 engines seem to be somewhat common. Had mine replaced under warranty. It was a very minor leak. Start by doing a search for "purge line" and check that. If that checks out OK, check back in and let us know.


when this happened i had to get home and it was all the way in the red . .to the point the car would tell me to pull over, and then the computer even overrides something and you cant drive past 2000 rpms . . or a speed, cant quite tell what its doing but its meddling
What you experienced was the "limp home mode" or "camel mode". The Northstar is designed to go 50 miles with no coolant to "get you home" or to a safe place. It alternately disables left and right bank fuel injectors, thus just pumping air through the cylinders to keep the engine cool enough to run, but you are only running on 4 cylinders.

C&C
07-13-08, 06:50 AM
If your coolant level is at 'full' level, and you are overheating, the most obvious reason (it wasn't mentioned that it was checked or eliminated as a cause) is the thermostat. Barring that, and if you are still overheating and the coolant level remains normal, then it could be a water pump problem or plugged radiator. Those are a couple of other things that need to be eliminated as causes. Good luck.

chubbyranger
07-13-08, 07:43 AM
Check the water pump belt and tensioner - going straight to overheat sounds like you have no coolant flow.

Mark C
07-14-08, 01:57 PM
Don't beleive there are any water passages in the intake manifold (at leasts theres not in a 97 my 00 hasn't been apart yet), so that can't be leaking coolant.

Hate to be the first one to say it, but a car that overheats to that extreme (250 plus) in 6 or 7 miles but the engine and radiator hoses feel cool to the touch, and your blowing water out of the surge tank overflow line the most obvious answer is head gaskets. Your most likely blowing exhaust gas directly in to the rear cylinder head water passages where the temperature sensor is. That is exactly what my 97 did before I did my head gaskets. My 2000 had a plugged purge line and the temperature increase was much more gradual and never got to the idle engine, or camel mode.

Go ahead and check the water pump to make sure its turning and the purge line for a plug, but also plan on getting the coolant checked for exhaust gases.

foos
07-20-08, 03:07 AM
hmmm. I'm having the same issue.. I was out doing some WOT's and then driving normally after that it got really hot and it said 'ENGINE HOT- AC OFF'
and stayed at that high temp all the way home .. The coolant seems full, and nothing is leaking, but squeezing the hoses that go to the thermostat area , usually you can't squeeze them very easily because of the pressure going through there but i could, I even revved up the engine while i was squeezing it and it didn't get more pressure..
Could the water pump be bad or the thermostat be stuck? Hopefully it's one of those and not something worse..
The water pump is definitely turning.. no leaks, no noise

1999 STS (110k miles)

Ranger
07-20-08, 04:55 PM
The water pump is definitely turning.. no leaks, no noise
The pump is fine. Check the purge line (quick, cheap & easy). If OK, rule out (or confirm) the worst case by getting the coolant analyzed.

foos
07-20-08, 08:37 PM
Which one is the purge line? The little hose that connects to the top of the tank and goes back into the TB?
I started it up after I let it cool down and let it idle for a while and it seems fine now.. Weird.. Probably thermostat or something got plugged cuz I was at 6000+ rpm many, many times within a short period :>

Will check it and see.. Probably time to replace thermostat anyway..
I have to replace all the brakes(rotors and pads), engine mount(s), tranny fluid, suspension sensor, cat converter, and some other random things..

Original rotors with 110k miles, original sensors and mounts, etc.. So I think that's a pretty good run considering that I beat on it the entire time :)

Ranger
07-20-08, 08:45 PM
Which one is the purge line? The little hose that connects to the top of the tank and goes back into the TB?


Yes.

foos
07-22-08, 08:27 PM
It all looks good now and it isn't overheating.. weird.. I'm going to replace the thermostat anyway.. Doing my 110k maintenance (o2 sensors, cat, pulleys, belts, engine mount, suspension sensor, rotors, etc etc etc) might as well replace it... I probably blew a chunk of crap off of something with all the WOTs :) I probably WOT almost every time I drive it, and I do a lot of chase camming with this car :) (chasing people who are street racing and filming it) on the weekends so it's WOT hundreds of times those nights :> , WOT 6600 rpm in 3rd gear (grin)

Ur7x
07-29-08, 06:24 PM
When you replace the thermostate also replace the water pump COVER... and gasket... very comon problem on 2000-2004 Northstars another source of "invisable" collant leaks. Cheap and easy to do while you are there.