: Coolant in my Oil



sofireguy
10-30-08, 11:06 AM
Is this a bad thing?? I've heard that 4.6L Northstars aren't suppose to let coolant in the oil when a HG is bad. I was wanting to swap this one out for another and keep this one as a back-up after doing the heads and HGs.

Was contemplating on doing like 97EldoCoupe:

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/153232-northstar-repair-without-inserts.html

Looks like a pretty good idea if my block isn't shot.

zonie77
10-30-08, 02:53 PM
Northstar's are resistant to coolant in the oil, not impervious.

codewize
10-30-08, 03:01 PM
The HG design on the N* is very resistant to allowing oil and coolant to mix. Only under rare circumstances will this happen. Most likely you have a crack in either a head or the block, both of which are also very very rare on the N* unless it's been frozen.

sofireguy
10-30-08, 03:55 PM
It doesn't get cold enough here in NC to freeze coolant. My dad switched from Dexcool to BMW's coolant formula which broke up a lot of the corrosion that the Dexcool left behind. Is it possible that the BMW coolant ate the gasket up enough to let coolant into the cylinder?

I do know that when we start it up every now and then there is THICK and I mean thick white smoke that smells like coolant.

sofireguy
10-30-08, 03:59 PM
So can I save my bottom end by changing the oil and not running the car?

Ranger
10-30-08, 04:24 PM
The head gasket is shot. Most likely the threads pulled and you'll need to Timesert http://www.timesert.com the bolt holes before putting it back together.

zonie77
10-30-08, 04:27 PM
So can I save my bottom end by changing the oil and not running the car?

Maybe, you haven't said enough to give you a yes or no. Changing the oil is the right thing to do even if you are going to let it sit.

Coolant doesn't eat HG's. I think they are all the same antifreeze with different corrosion inhibitors.

The Dexcool was depleted and should have been changed sooner.

codewize
10-31-08, 01:00 AM
Right, the Dex doesn't leave corrosion, it just wasn't changed on time.

This is one of the things we stress around here. If there's anything, one single thing at all, that one can do to try to avoid HG failure, it's to change the coolant on time.

Lack of maintenance = primary cause of failure.

sofireguy
10-31-08, 01:06 AM
Well, It wasn't originally my vehicle. But I always maintain my vehicles for preventative purposes. We were just caught off guard by this Northstar. Didn't know what we got into at first. But, it's over and done with, HG needs replaced no matter mow much we talk about coolant now. Just hope the bearings didn't corrode at all...

codewize
10-31-08, 08:27 AM
Well change the oil, get that crap out of there. The bottom ends of the N* are very tough.

How long has this condition existed, that you know of?

Also consider a reman engine before doing HG replacement. It may be less costly, especially if you have to open up the bottom end.

sofireguy
10-31-08, 12:14 PM
Well as soon as we had the overheating problem, we sat the car. A week after taking it off the road we were doing checks on oil, cooling system. I drained the oil and there was ~1/4 gallon of coolant in the oil pan with the 6 quarts of oil. I changed the oil and ran the car to circulate the oil. And it's been sitting for ~6 months now, but we start it up every now and then. Might need to Seafoam it after a HG job if the cooling system doesn't look too bad when the heads are off.

codewize
10-31-08, 12:27 PM
I would just keep the oil clean, do the job or replace the engine. I wouldn't do any seafoaming or anything.

Just nice new oil and nice fresh Dex. You may even want to plan on a change of both shortly after the rework.

I'm not sure what it takes to thrash bearing these days but you may be OK. Seriously if there's any question at all about that I would consider a reman.

Mark C
10-31-08, 01:23 PM
If you have an oil cooler in your radiator, make sure that you get that tested for a leak. Thats the most obvious way of getting water into your oil.

Ranger
10-31-08, 10:08 PM
:yeah:

codewize
11-01-08, 01:26 AM
Ahh good call. I know that and I always forget to mention it.


If you have an oil cooler in your radiator, make sure that you get that tested for a leak. Thats the most obvious way of getting water into your oil.