: i need help on how to change my headgasket on my 99 seville sls

07-22-07, 05:44 PM
my car temp is starting to go up more than unsual and i needed to know where i can get some instructions how to change my headgasket besides taking my car to the dealership because i have a haynes book and thats all it says and it says req. special tool can somebody help me

07-22-07, 06:13 PM
throw away your Haynes books and get the GM Service Manuals for your Seville on ebay. That is my suggestion if you really want to do the gaskets yourself...of course others will ask you:

1) are you sure its the head gasket, and how do you know for sure?

2) are you prepared to pull the engine out of the car?

3) there will be more questions!

07-22-07, 06:13 PM
AAACK! just behing TarQ!!!!

First, I wouldn't jump in to anything as complex as a HG swap with a Haynes manual. IF you need to R&R the gaskets, you NEED, repeat NEED a copy of the Factory Service Manual - from Ebay, or HELMS.

But foist, as they say, the HGs are the LAST thing I'd fall back on - there are about a dozen other reasons why your temps might be rising.

Search on COOLANT TEMP or WATER PUMP or THERMOSTAT and see some of the posts.

There are at least a dozen checks to go through before you attempt the HG repair. Read up, and get back to us with more details...

07-22-07, 06:38 PM
Unless you've cracked open a northstar before, I don't suggest attempting to repair it yourself. The motor must be dropped (with the subframe) out the bottom of the car. Then all 20 headbolts have to me retapped into the block with timeserts. You've got to make sure the heads aren't cracked or warped from overheating as well. I mean, you could try it, the motor is screwed anyway.

07-22-07, 09:02 PM
my car temp is starting to go up more than unsual
He hasn't gotten hot enough to warp heads.

07-23-07, 04:40 PM
get a new motor... i have the same prob myself on my 99 sts its prob best if u get a referb n* i got a # to a guy he said the gaskets wont go as easy after he remanufactures the motor..... pm me if u want the #

ps.. he has the vin-y motor u need in stock

07-23-07, 05:13 PM
I also recomend getting the refurb motor if it is the guy in Wisconsin I would use him.

07-23-07, 09:05 PM
First, make sure you have a HG problem. Take it to a radiator shop and have them do a coolant byproduct test. They are cheaper and faster than a mechanic...and they usually do it more often.

Second, If it is HG's...If the engine is still running well the best thing (if you are doing it yourself) is to replace the HG's and repair the bolt holes on your own engine. Some of the bolt holes are usually damaged and require a special insert to repair. Helicoils are NOT strong enough. If you engine has been running well you might as well fix it. N's are good for 250,000 miles with any reasonable care.

Third, It is possible to repair this yourself. The N is not a mystery engine that requires supernatural powers to repair. Many of the forum members have done them at home. It is a long job though. Because of the tight fit of a FWD V8 there is little room to work on the back head and on the timing cover. It is easier to drop the engine/cradle assembly, repair the engine, and reinstall it.

It is a long job though. You have to have perseverance! You do save a bunch of money though. Depending on what you have to buy it could be as cheap as $300 or as much as $1000.

Here's a write up I did after the first one I did.


07-23-07, 10:02 PM
I also recomend getting the refurb motor if it is the guy in Wisconsin I would use him.
If you are talking about Custom Innovations, you better do a search.