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1999 Deville
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39 Posts
Discussion Starter #1
Lately I have noticed a coolant loss. After I fill the reservoir tank about half way I drive for about 30 miles and notice that the temp steadily rises sometimes up to 250 with ac on going uphill. I can't seem to locate a leak since I don't see any coolant on the ground after I shut it off and park it. I checked the purge line and coolant is flowing into the tank. I have a new reservoir tank and I plan to replace the one that's in there but i don't know what good that will do. while I'm doing that I will clean out the purge line. While I'm stopped in traffic the temp will go from around 196-207 up to around 230. One I start driving again it takes a long time for the temp to drop back down to normal. why does iit take so long for the engine temp to cool down while driving on a level surface? The system seem to lose about a quart of coolant every 30 miles. I can't trust the car on a 100 mile trip or going up steep hills for fear of overheating. any suggestions would be most welcome . thanks
 

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1998 DeVille
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111 Posts
Going to go ahead and tell you the first thing you'll hear.... Go get a block test done. The symptoms are congruent with a head gasket.... The other possibility is to make sure your purge valve isn't clogged. Give me a minute and I'll edit this with a link to a post discussing how to do that
 

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2000 Deville Base, 2019 Corvette Grand Sport
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1,092 Posts
Don't like saying this but 1999, worst year for head gasket failure.
 

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1998 DeVille
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111 Posts
584433


I bypasses the throttle body on mine, so it looks a little different, but the circle is the purge valve. The squiggles are the standard route for the hoses. Pull the small hose off the outlet there, and the remove the bolt shaped outlet. Make sure that isn't clogged
 

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1996 Deville
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31 Posts
Going to go ahead and tell you the first thing you'll hear.... Go get a block test done. The symptoms are congruent with a head gasket.... The other possibility is to make sure your purge valve isn't clogged. Give me a minute and I'll edit this with a link to a post discussing how to do that
... I'm having damn near the same issue ... and driving these guys nuts with it ... my first estimate was $3200 for head gasket repair. Been watching videos on Bars head gasket repair liquid although these guys hear aren't much for hearing that crap. I ordered the chemical block test kit and awaiting it's arival. Decisions decisions ... guess it all comes down to what the car is worth to you ... how much money you have ... how many tools you own ... and how much time and patience one posseses ...
 

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2000 Deville Base, 2019 Corvette Grand Sport
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1,092 Posts
... I'm having damn near the same issue ... and driving these guys nuts with it ... my first estimate was $3200 for head gasket repair. Been watching videos on Bars head gasket repair liquid although these guys hear aren't much for hearing that crap. I ordered the chemical block test kit and awaiting it's arival. Decisions decisions ... guess it all comes down to what the car is worth to you ... how much money you have ... how many tools you own ... and how much time and patience one posseses ...
Ordered? You can walk in any of the major auto stores and buy the solution and borrow the kit.
584435
584436
 

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1999 Deville
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39 Posts
Discussion Starter #8
Thanks folks. I will follow your advice and do the stuff. I'm not getting any white smoke out the tail pipe though. should I go ahead and change the tank too since I have a new one?
 

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1999 Deville
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39 Posts
Discussion Starter #9
I have a bottle of Bars head gasket repair. It will be my last resort. the caddy is a beautiful ride, it's only got 76k miles and looks like new but I just can see spending big bucks on this problem. I hope these instructions will get it fixed. thanks again.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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87,173 Posts
should I go ahead and change the tank too since I have a new one?
May as well wait until you get the results from the block test and then go from there.


I would not recommend using any Miracle-In-A-Bottle snake oil in it. At very best, it may buy you some time, but probably very little based on what you said, "The system seem to lose about a quart of coolant every 30 miles.".
 

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1998 DeVille
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111 Posts
What you have to understand about the northstar is that the coolant system never has a sidewall with an oil passage. You'll never see the white smoke or the oil in the coolant. what you will get however, is exhaust gasses seeping through between the spots where the head bolts have loosened. Since the head gasket is compressed, it holds its form as the head itself lifts minuscule quantities at a time, while the head bolts, which are torque to stretch, slowly pull out from the excess load.

Its a doable job. It's worth dropping some money at harbor freight on some better tools. everything that ratchets and wobbles.

I'll have videos up soon to show how to remove, and I'll be be doing videos on the serts, and reinstalling the whole thing.

Cure in a bottle will only slightly prolong the inevitable, as the bolts will keep pulling. Take that money and start saving it for the serts, and the rest of the tools you need. You can do this
 

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1996 Deville
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31 Posts
... I'm in the exact same boat as everyone is getting sick of hearing. My chemical test kit will be hear soon , I know I coulda got one local ... anyway ... I admit I've been researching the Bars too ... but if you post these videos and make it appear doable maybe we'll change our minds. Victus, my one price from one mechanic so far was $3200 ... says he's done over 100 of them. Did you get a price yet? What scares me off is when I watch other videos about doing the job right and the timing chain and all this other crap has to be messed with and it makes me feel like I'd never get it back togther correctly. I fear I'd put in all this time and turn on the car and ... all this fluid would fly everywhere and I'd be pissed and dissapointed. Maybe the videos Juggastoned posts will make it seem less daunting. Thanks for all the advice guys, even though I have been driving you crazy ... even though you said the oil and coolant passages aren't "close" I swear when I stick my finger into my coolant purge tank I feel a thin layer of what feels like oil slime on the surface and it seems to smell a bit of oil. Not a ton , just a bit ... and one of my last questions concerning the HEAD BOLTS ... I know CADDY are notorious for them going bad ... but isn't there a chance you could have one with a HEAD GASKET failure ... that wasn't the head bolt issue in some cases? Just a HEAD GASKET failing from some other reason?

May as well wait until you get the results from the block test and then go from there.

I would not recommend using any Miracle-In-A-Bottle snake oil in it. At very best, it may buy you some time, but probably very little based on what you said, "The system seem to lose about a quart of coolant every 30 miles.".
ME, I'm not losing any coolant, no white smoke, no milky oil, trace of what appears to be oil in purge tank, idles in drive with A/C on mostly fine at 199 ... turn off A/C today in this brutal heat still in driveway and it climbs to 222 when the low fan kicks in and gradually goes right back to 219,217,213 212 .... raises back to 222 then back down again ... it's mostly after that 30 minute drive where that spike up may or may not happen ... it might hit 233 and come back down ... it may hit 233 and run away to 255 ... you never know which ? It sure is agravating ... I'll update when I do the chemical test ... purge hose runs clear .... engine runs great ... a misfire here or there .... I have one last desperate attempt with the air filter ... as I've read , dirty filters can cause misfires which can cause overheating ... after that ... prolly the head gasket .... :(


Going to go ahead and tell you the first thing you'll hear.... Go get a block test done. The symptoms are congruent with a head gasket.... The other possibility is to make sure your purge valve isn't clogged. Give me a minute and I'll edit this with a link to a post discussing how to do that
NOt being a jerk but I'm wondering why you suggested he check the purge line when he already said he did and it was flowing fine?

Thanks folks. I will follow your advice and do the stuff. I'm not getting any white smoke out the tail pipe though. should I go ahead and change the tank too since I have a new one?
Curious, who suggested you buy a new surge tank and why? Is it because you think it could be leaking somewhere you cannot see or some other reason? I was looking closely at mine today ... wondering if the BOTTOM hose could be clogged or partially clogged ... as my purge hose is flowing pretty steady it appears ....

... and another thing ... can you only replace one of the two head gaskets? If say, you find only the cylinders on one of them are affected? Front or rear but not both?
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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69,785 Posts
Your question about repeat purge line test questions - several members are trying to help the OP by posting to this thread - and we sometimes trip over each other's feet.

Do both heads at the same time. Not only do you kill two birds with one stone but you also even out stresses in the block/head assemblies.

You are in Ohio - contact Joe Blau at Midwest Cadillac Repair in Palatine, IL. Just west of Chicago. He's the resident expert at inserting Northstars - probably done over 800 - yes, 800 - by now. Top notch work and relatively inexpensive. Either limp or truck the car there.


CURE, Based on several of your posts and threads I'd respectfully suggest that you let an experienced Northstar shop do your repair/maintenance work.
 
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