: Overheating after new headgasket

03-25-08, 12:12 PM
Hey, I have a 1997 Eldorado with a 3.8L Northstar Engine.

I had overheating problems when on the highway last year and had the headgasket replaced.

Driving back to school last weekend from spring break, i had the same problem.
I checked antifreeze level, oil level, basic hoses (to see anything obvious) and i couldn't figure it out. There was a lot of pressure building up in my tank for the antifreeze and when i released it, a good amount of antifreeze leaked out the bottom of my car. The antifreeze was also very hot. I also noticed that there was a little bit of smoke coming up from my steering column, it was only periodic and a very little each time.

If anyone has any ideas why it's overheating again or has had a similar problem and knows a fix that would amazing.

Thanks a lot, Cody.

03-25-08, 12:24 PM
Ruh-Roh! Did they "insert" all 20 holes in the block when they replaced the HGs?

03-25-08, 12:48 PM
I'm not sure actually... I can call them after class and see if they have it on record. What exactly would not having all 20 do?

03-25-08, 01:13 PM
Minor mistake but you have a 4.6L Northstar :) If they didn't use timeserts or norm's inserts the aluminum threads may have broken off when they pulled the old bolts out, that being said when you put in new bolts there's only part of the thread so the bolt doesn't carry the proper load and the head will lift and you can have overheating. Make sure your shop did NOT use helicoils as they are not strong enough and are not the approved method for repairing a N*. I'd check all your belts, your waterpump, radiator, you may try flushing the system to make sure there's no clog somewhere.

Also, you know you should never open the surge tank or 'antifreeze tank' as you called it while at operating temps as as it's operating under 15lbs of pressure which when removed can cause the coolant to instantaneously boil and bubble out and burn you!? Also it expands, that's why it went all over the ground. How hot did it get? Where was the coolant needle? Are you blowing white smoke out the tailpipe while it's running? Is the car running real rough like it's misfiring? There are numerous tests to be done to check to see if your HGs are leaking and 2 most effective are a leak down test (while watching your coolant surge tank for bubbles, and a dye test of your coolant for the presence of hydrocarbons (i.e. combustion gases).

03-25-08, 01:39 PM
Find out exactly what they did. Both HG or just one? Did they insert some or all bolt holes? Was the cradle dropped or engine pulled to do HG's ?

It could also be a straightforward overheating problem. Check the water pump drive belt and replace the cap if it isn't brand new. Also check the purge line to the surge tank. Have the coolant tested for exhaust gases, you can have a radiator shop do that.

03-25-08, 01:44 PM
Yeah - what RAZE said, except maybe the white smoke out the tailpipe - in my experience (2 blown head gaskets on 2 Northstars, the exhaust gases get into the coolant, not the other way around.

03-26-08, 12:13 PM
my gasket popped such that coolant leaked into the cylinder and burned off during combustion, was quite a sight to see!

03-26-08, 01:39 PM
Cooool! There must have been huge plumes of steam? I thought I had read that was not common - I guess maybe I was mistaken