: 01 Northstar Water in oil, high oil use, misses when cold.



Ag_teacher
05-05-14, 12:52 AM
I'm hoping somebody has an idea of the problems with this car. Otherwise it will be going to the scrap heap. I have a 2001 Deville base model with 149,500 miles. I bought it a year and a half ago at 128,000 and it used about a quart every thousand miles, and ran good. This winter it started putting oil in the coolant. I discovered this in March
when I had to replace the thermostat. I decided to clean the burp tank out and see if it did it again. It did. It then developed a miss at cold startup and the last time it was
driven it went through a quart of oil to do a 35 mile round trip.

Here is a little more of what I know. It does not have an oil cooler, Compression is approximately 175 on all eight holes. I pulled the engine and the head gaskets were still good. My father in law, who is a mechanic, measured the cylinders to see how badly the bottom end is worn, and cylinders are still in spec. Valve guide seals still look good and very little play on the valve guides.

Any ideas? We are stumped and I don't want to tear it any farther unless I need to.

MoistCabbage
05-05-14, 01:20 AM
However you checked that the HGs were still good, was either done incorrectly, or was the wrong test (compression test?).

It's an HG issue.

Ag_teacher
05-05-14, 01:36 AM
My test is this: I've got the heads sitting on my bench. No holes or tracks between the oil ports and any other part of the head. Oil was were it was supposed to be and water was where it supposed to be. Flat dry gasket in between.

MoistCabbage
05-05-14, 01:47 AM
Well now that the heads off you know you have to insert or stud the block before reassembly, right?

Unless the block is cracked, or you have an oil cooler, there's no other possibility than HGs.

Ag_teacher
05-05-14, 10:01 AM
Thank you for your help.

I'm looking at going with a stud kit.

I made the assumption of head gaskets with the symptoms it has, which is why I pulled the motor, but with the gaskets appearing undamaged, I'm not so certain. Shouldn't the head gaskets show evidence of leaking somewhere around the oil ports? Especially with the amount of oil this thing is using?

Are there any locations to look that they are prone to cracking the block or head?

Ranger
05-05-14, 11:26 AM
Wait a minute. You said "it started putting oil in the coolant", but your title say's "Water in oil". Which is it?

If the gaskets were bad, there should be some evidence.

Did all the bolts "crack" when loosened? Was there any evidence of aluminum in the threads?

Ag_teacher
05-05-14, 11:45 AM
Sorry, it looks like I miss titled it. I just fixed that on the thread title

Anyways, it's oil in the water, no evidence of bad gaskets, and all of the bolts did crack. there was one with evidence of aluminum in the threads (bottom two or three threads), but it was on the exhaust side of the head and in the middle.

Submariner409
05-05-14, 11:59 AM
........... and/or the transmission oil cooler has developed a small leak. THAT would put oil directly into the coolant. Highly unlikely that a base Deville has the V03 HD cooling with engine oil cooler in the passenger side radiator end tank.

Excessive oil consumption with no apparent gasket failure might be caused by severely worn/stuck piston compression and oil control rings (and/or valve stem seals) - but that doesn't explain the oil in the coolant, which is rare for Northstar. New rings and rod/crank bearings, new rear main seal. You don't hone Northstar cylinders and you don't install undersized bearings: new crankshaft.

Ag_teacher
05-05-14, 02:08 PM
Transmission doesn't seem to use any oil. Never had to put any fluid in it.

We were also thinking about the bottom end problems, but not being real familiar with a northstar, I wanted to make sure there wasn't something we missed somewhere along the way. The
problem is that with the overall it will be way over budget and more than the car is probably worth. A different time and place I wouldn't think twice about fixing it, but right now I'm a little limited on options

Thanks to both of you for the information.

Ag_teacher
05-06-14, 09:04 AM
My curiosity is getting the best of me. Why do you not hone the cylinders or install undersized bearings? Any other tricks to be known about rebuilding one?

Submariner409
05-06-14, 10:21 AM
Stock Northstars use low tension compression rings and a very aggressive CNC controlled cylinder honing process. A 150,000 mile Northstar still has most of the crosshatch in all cylinders. The crank uses rolled radius journals and reconditioning machines in the field do not duplicate that radius - stress relief.

GM does not recommend boring for any oversized pistons or ring sets, and they do not use undersize bearings either. They ARE available, but not for GM-recommended overhauls.

The GM service manual has specific rebuild procedures for these critters - it ain't a SBC !

If you're a DIY gearhead, get a real GM/Helm service manual set from either www.helminc.com, from eBay, or consider a multi-year subscription to www.alldatadiy.com. . For parts, look into RockAuto, talk to Chris in parts at Rippy Cadillac over there >>> or talk to Jake at www.northstarperformance.com .

Ranger
05-06-14, 11:26 AM
Here are a couple of cylinders at 130 & 170K. Pretty nice eh?

rodnok01
05-06-14, 11:52 AM
It is amazing how well the cylinders hold up even when HG are shot... Didn't get that from a SBC.
If you think about it other than too fine a thread in the block these are pretty damn tough and powerful engines.

04GrandAmGT
05-06-14, 01:21 PM
........... and/or the transmission oil cooler has developed a small leak. THAT would put oil directly into the coolant. Highly unlikely that a base Deville has the V03 HD cooling with engine oil cooler in the passenger side radiator end tank.

Excessive oil consumption with no apparent gasket failure might be caused by severely worn/stuck piston compression and oil control rings (and/or valve stem seals) - but that doesn't explain the oil in the coolant, which is rare for Northstar. New rings and rod/crank bearings, new rear main seal. You don't hone Northstar cylinders and you don't install undersized bearings: new crankshaft.

i dont think even the DTS had oil coolers from 00-03, only the seville STS and the edlo ETC. dont quote me on that but im almost sure.

----------

i will double check with my DTS when i get home, this evening.

Ag_teacher
05-06-14, 02:12 PM
The cross hatch is still good. Half the reason I'm looking at rebuilding is to see how this thing is set up. It is impressive to check out. It is nothing like my two old 79 GM pickups.

I've been getting most of my information off of the forum and alldata. I have an old laptop for the purpose of working on these.

Also, I'm leaning towards going with a stud kit. What is out there for options on these?

RippyPartsDept
05-06-14, 04:52 PM
what about a cracked block?

that would mix oil and coolant and also be hard to see

Submariner409
05-06-14, 04:53 PM
Communicate directly with Evrett or Jake at www.northstarperformance.com (http://www.northstarperformance.com) - Evrett has the post before your last one.

Good call, Chris (RippyParts) - that went right over my head earlier today.

Ag_, There are a few other options for Northstar cylinder block bolt hole repair - but the recommended studs are the most elegant. An alternative fix is to use new GM head bolts with Norm's inserts - www.huhnsolutions.com (http://www.huhnsolutions.com).

Ranger
05-06-14, 10:23 PM
It is amazing how well the cylinders hold up even when HG are shot... Didn't get that from a SBC.
If you think about it other than too fine a thread in the block these are pretty damn tough and powerful engines.
That is the one weak link in a mighty fine chain. Too bad GM didn't address it sooner. Damned engine would have been bullet proof.

04GrandAmGT
05-07-14, 11:13 AM
what about a cracked block?

that would mix oil and coolant and also be hard to see

definitely a possibility, but they normally only crack in one of two places, the cylinder wall which is very easily seen by the naked eye, aswell the side of the block. and that can be seen easily too, though im not saying its impossible that there could be a small crack hidden but, these are the most likely places.

PaleAle
05-07-14, 10:13 PM
It's not always easy to tell exactly where the head gasket failure was when you replace them. When coolant does get in the oil, it's a 2way street, oil gets in the coolant too. It makes a mess. I agree that you should try to determine if there's a crack, otherwise I'm betting on the gaskets even if they didn't show signs of failure.