98 Eldo Unstable Engine Temp

[MtlSphere]

So...I'm driving along when the radio goes quiet and all sorts of bells and bongs are going off. I look down at the guages and the coolant temp is pegged. I pulled off the street to let it cool but every time I started it I could only go a few blocks before it krept into the red again. I repeated this until I got home. Thinking the thermostat had failed i bought a new one, new dexcool, and mobil 1. I drained the coolant, removed the thermostat, replaced the housing and flushed the system. Nothing unusual came out and flow was unobstructed in all directions (top to bottom / bottom to top / recovery tank). I put the thermostat back in filled it up with 50/50 dexcool, changed the oil and filter...but...

The normal guage operation has been straight up under normal driving. Now that's the coolest reading I get while driving. I thought of fan relays but this occurs even while in motion, not just at stops and idle.

So here's my question...

The water pump on the N* is belt driven from the camshaft. Could the belt be slipping or the tensioner failing allowing belt slippage? Is this an issue with the N*? At any raye the belt is like $7.00 at auto zone so I think I'll replace it anyway as it's almost certainly as old as the car. :Bang

 

[MAC1]

I suppose it's possible the belt is slipping, but not likely. Do you see any bubbling in the expansion tank, which is indicative of a blown head gasket. Is there a smell of fuel or exhaust in the anti-freeze? If heated gases blow-by the head gasket it will cause the water to get abnormally hot. This has happened to other Northstar owners.

 

[DJ Kontakt]

im going to guess its a blown head gasket. Does the car run like crap, even when it idles?

 

[RazeOrc]

If the car is old check to make sure u don't have a malfunctioning thermistor, they're cheap and can be replaced somewhat easily. You need to check your coolant level, is it dropping noticeably or are you having to refill it often? Is there any white smoke coming from your exhaust (not steam), or can you smell coolant while driving, after parking? Does you engine misfire or idle rough? If some or all of these symptoms are occuring you need to check for blown headgaskets, in order to do that you need to do a compression test on each cylinder to ensure it is maintaining 120 psi, you should check the 'other' cadillac forum out there as it is a widely discussed topic in the 'northstar technical discussion board'

 

[Bob]

very intresting!

I find your cooling problem answer very intresting. I have a 97 with an intriguing cooling dilemma,that I'd like to kick around if you'd like. Two questions please..what is a thermistor & what and where is the "other cadillac forum" Thank you...Bob Quinn

 

[CaDreamr]

RE: Temp Status

I have a '98 and my temp always reads straight up in the middle is this not normal for this car? I'd thought maybe it was since it's never read anything else since I bought it at the end of '04. If it isn't normal what can I do to check and see what the problem is? Any help or advise would be appreciated. I've had to fix and replace a lot of parts since I purchased the car because the last owners (who leased the car out) obviously never took care of it - even the spark plugs & wires looked like they hadn't been changed since the car was first purchased! It's such a shame that such a beautiful car was treated so poorly. Thanks!
Tricia :C

 

[MAC1]

Tricia,

It sounds like your temp is fine. If you’re saying that your temperature or needle reads in the middle between cold and hot, it means you're OK. I think that you should be able to program the PCM to check via digital readout as well. Most important regarding maintenance is that you change the anti-freeze at least as recommended. Neglecting anti-freeze can bring about serious problems, including blown head gaskets, insufficient cooling and, of course, freeze-ups.