: northstar head warpage?



david_peak
10-22-03, 12:33 AM
I am thinking about buying a 97 deville concours, Immaculate condition inside and out and extremely cheap($3000). The only problem is both head gaskets are leaking. Car runs perfect until it warms up completely , then white smoke comes out of the exhaust. I can install new head gaskets and heli-coils with no problem. My question is how bad are these heads about warping? I'm thinking that if the heads are reusable most of the time, it would be worth getting the car. But, if they are bad about warping, buying new heads would make it a bit expensive.

Also, does anyone have any recommendations for a seller of good cyl heads, just in case? 97 deville concours 4.6L (vin Y)

Any advice or experiances are greatly appreciated.

zonie77
10-22-03, 01:24 AM
I am doing the heads gaskets on my brother's 94 STS now. We pulled the engine over the weekend so we havn't taken it apart yet.
There is some info floating around the board. I havn't seen much about bad heads, most of the problems seem to be pulled threads in the block. Time sert is the recommended repair, not helicoils.
http://www.timesert.com/
The kit is $295 and you need 10 more inserts at $2.65 each. We just ordered a kit Monday.
I had seen info that 96 and newer blocks were inserted from the factory but I could not find an official mention of this.
You seem comfortable doing this. Do you have a lift available? We used an engine hoist to raise the body enough to clear the powertrain. Then slid the powertrain out on 2 jacks. Set it on blocks to work on the heads.
Is the DeVille RW drive? That would make it doable without dropping the engine.

Katshot
10-22-03, 05:51 AM
There's no way to know how bad they are without a machine shop to check them. Best rule of thumb is to remove them and send them out for rebuild or to be swapped. Then go back with Time-serts and new head bolts.

zonie77
10-23-03, 01:24 AM
The gaskets and head bolts show available at Checker/Shucks/Kragen.

After all the work to pull them I think they at least should be checked for cracks.

david_peak
10-24-03, 08:23 PM
absolutely! I am definitly sending it to a machine shop for pressure test and if necessary, machining. I was just wondering if the heads have a tendancy to warp on this type of motor. It did overheat, not severly though. It runs perfect until it heats up, then white smoke comes out of the exhaust. Do you think this would this be enough to warp the heads beyond the sevicable limit?

Thanks for all the good advice

eehoepp
10-25-03, 07:09 PM
There's a few threads here where I've thrown my $0.02 on the head gasket / head bolt / TimeSert questions.

My car overheated due to pulled threads. I was in the middle of nowhere on a cold and rainy December evening. I took advantage of the "run 50 at 50 without coolant" feature Cadillac advertised when they first introduced the Northstar. The DIC told me "Engine overheated. Stop engine now." (or something like that) more than once. I stopped to let it cool a while, then started it back up & drove it until the message showed again. Knowing what I now know about these engines, I don't think I'd do that again. All told, I think it was about 35 miles I drove that way.

I would consider this experience to be a fairly major overheat. When I had the heads off I checked them with a precision straightedge & precision feeler gauges. They were not warped.

The engine had 93000 miles then and is now at 103000 with no problems.

Your mileage may vary.