I have a 1998 Cadillac Eldorado with a Northstar engine. As is common with these cars, I have a cracked head gasket(s). I have read on the cadillacforums website that the liquid repair products may work for some vehicles, but not the Caddy’s because over time the bolts on the aluminum heads separate and no amount of “cure in a can” will seal the problem. I am far from a mechanic (I have trouble changing a light bulb… okay, it isn’t that BAD, but close). The aforementioned forum has a few folks with over 5,000 posts that seem to be authorities on the cars, but I have to wonder if I’m getting straight talk from them and their opinions, or if the Bar’s Leaks Head Gasket Repair product MAY work. I’d LOVE for anyone that has used it on a Cadillac to advise of their success or failure, and any moderator to this site to chime in with their input. It will be highly regarded. Thanks!
I tell people, if you’re going to attempt to get a few more miles out of an engine with an internal coolant leak, instead of spending the $50.00-$70.00 for a product with a fancy name in a fancy bottle, call a local pharmacy and order a bottle of sodium silicate for about $20.00. Sodium silicate is the primary ingredient in those high priced stop-leak products.
Sodium Silicate is what they dumped in the crankcase of all those “Cash For Clunkers” to positively destroy their engines…In a cooling system, I suspect the water pumps life may be very short indeed at this stuff is VERY abrasive…
"Dealers must replace the oil in the “clunker” with two quarts of sodium silicate solution and run the engine for up to seven minutes, permanently disabling it, according to rules released today by the National Highway Traffic Safety Administration in Washington. "
I’m afraid your Eldo has come to the end of it’s useful life…The NorthStar engines are not designed for “field repairs”…and GM has stopped using them…So sure, try a “Miracle in a can” as you have nothing to lose…
If its the kind of car that you really love and want to keep indefinitely, then you find your best local, independent shop that does work like this and have the heads done.
If you just want to try to eke some more miles out of it before selling if for scrap then, as noted, you’ve got nothing to lose by trying the stuff.
I had the engine completely removed and the heads done by the oldest Cadillac dealership (huge) in the US (here in Jacksonville, FL). One year and two weeks later (14 days beyond the warranty) the car overheated and the gaskets had cracked again. Granted, all this happened over a year ago, so my memory is a little blurred. After spending $4000 to do it right the first time (including a sealing of something - I forget - maybe it was the crankcase - as I have read they were designed as a split-piece), I just haven’t been able to bring myself to spend that kind of money again (and don’t have it). When I told my rep at the dealership what had happened, the only question I remember them asking was if the car had run hot prior to this happening. I remember about a week before, it was running about 1/4th hotter than the usual idle, and I didn’t take it to them - I added some Dex to it myself. When I told my rep that, he explained that the coolant is a closed system and should never require adding more - just changing at the recommended intervals - and placed the blame on me for not bringing the car in then. The car has 114,000 miles on it and is in beautiful shape - it is just a shame that it seems a bit hopeless to trash (or part-out) something in such good shape.
The N-star engine was designed by Lotus as a racing engine…They never used it…GM bought Lotus 20 years ago and used the engine design in Cadillac’s starting with the '92 Allante…The split crankcase design and 4-valve heads proved troublesome and high-maintenance but the performance was outstanding…The cost of pulling the engine to remove the heads or re-seal the crankcase, common problems, was prohibitive. Repairs done in the field were seldom successful as the skill level required to reliably assemble the engine simply did not exist outside the factory…Many owners will tell you it didn’t exist inside the factory either…
It doesn’t matter how well the engine was originally built or how well it was repaired if the engine is overheated and the driver continues to operate it while overheating. Especially so when aluminum is involved.
No engine or head gasket repair will last if the temp gauge needle is pegged on the H for who knows how long.
An additive may help some if a coolant leak exists that does not breach one of the combustion chambers. If a CC is breached then any additive is a waste of time in my opinion. My opinion is not Cadillac specific; it applies to any make or engine.