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Using coolant

I have a 2001 Cadillac DTS. The “check coolant level” warning came on, I added 1 quart, then about 2 days later the warning came on again. I added another quart and 2 days later the warning came on again. There are no visible leaks and no coolant on the garage floor under my car.

You Could Be Leaking It Inside The Car Or Burning It In The Engine
Check the floor inside the car for coolant. A bad heater core can leak inside. This would usually steam the windows up. Next, look for any signs of coolant stains under the hood. That’s quite a bit of coolant loss. I suppose it could be steaming out of a pin-hole in a hose when hot. A bad intake or head gasket could allow the engine to burn coolant with the fuel mixture. You should notice a rather smokey (steamy) exhaust, especially when it’s cool and humid outside, compared with other cars.

I would strongly suspect that you have a leak in the intake manifold gasket. This is a known problem with the design of the Northstar engine, and as far as I recall, your car does have the Northstar engine.

If you are very handy, you may be able to handle this repair job yourself. If not, expect to pay about $1,000. for a mechanic to do the job for you.

Since this problem has the potential to dilute your motor oil with coolant, if this is not attended to promptly you could suffer bearing damage, with a resulting repair bill of many thousands of $$, unfortunately. Sorry to be the bearer of potential bad news!

Yes, I do have a Northstar and I suspected it might be the intake manifold. I’m pretty handy, but not enough to tackle this job. I’m a 59 year old female. I think my best bet is to take it to my mechanic ASAP. Thanks for your help.

It is a documented fact that GM’s Dexcool antifreeze caused deteriation of the gaskets in many engines. You probably have a head gasket or a manifold gasker leaking. I had this problem with a '99 S-10 and ended up replacing the bearings in the engine.

I had a similar problem with my 2004 SLS (not as much though). I had took my car to the dealer twice and they could not find a leak (this was over a year ago). I decided to keep a log and was adding maybe 20 oz every two weeks. I took it back a month or so ago and they had a technical bullentin that talked about a crossover leak. They ended up replacing the manifold gasket, water pump, thermostat and housing and something call a plenum. Since my car is still under warranty I have no idea how much the repair cost was.

I’ve NEVER heard of the antifreeze causing problems with the head gaskets. Just the intake manifold gaskets that use silicon.

That is sweet for you! I had my coolant changed at 100k and my idnependant guys put in peak global? I had been reading about dexcool gunking up due to oxygen exposure, Is dexcool trouble in the making?

Well, maybe it was just the manifold gaskets, but the coolant can get into the cylinders and cause much damage.

There is nothing wrong with Dexcool. The problem is in letting ANY “permanent” anti-freeze stay in an engine for more than, say, 2 years or 50,000 miles whichever comes first. GM made the mistake of claiming longer life for Dexcool and people did not change it. Additives wear out that prevent dis-similar metals (aluminum, cast iron, copper) from galvanic reactions. That’s what eats up gaskets.

Close, but no cigar.

You are right about the Dexcool. (millions will disagree)

The poorly designed gaskets and the fact the intake manifold corner bolts had NO loc-tite on them caused all the problems.

AFTER the bolts came loose the coolant mixed with the air and trouble began, big time.

IF those bolts had stayed tight, there never would have been a mess.

Roadrunner is correct…The gaskets GM used along with the Dexcool antifreeze was a bad combination. This design affected MILLIONS of vehicles sold by GM. Friend of mine who owns a GMC truck/Pontiac dealership had to hire a extra mechanic several years ago just to handle this problem. There are several aftermarket fixes that was actually being recommended by GM to it’s dealers to fix the problem.

Well I know that there was a class-action lawsuit that was won against GM for the use of Dexcool. I had an S-10 that had to have the manifold gasket replaced and later had to have engine bearings replaced.