My first UOA.


Took six months to put 3713 on this oil. Installed MG bypass w/ sandwich adapter 2584 mi into the OCI and added 0.75 qts. extra oil. EaO filter, new Wix air filter at beginning of OCI. 600 mi. into the OCI CEL code P0442 and replaced the gas cap. No CEL since. Truck has 70,029 miles total.

Test results/universal averages
Aluminum 2/3
Chromium 0/1
Iron 5/14
Copper 35/5
Lead 6/8
Tin 0/1
Molydenum 42/65
Nickel 1/0
Manganese 0/1
Silver 0/0
titanium 0/0
Potassium 121/8
Boron 81/37
Silicon 20/18
Sodium 6/10
Calcium 2987/1972
Magnesium 12/147
Phosphorus 642/732
Zinc 768/884
Barium 0/0

SUS Vis. @ 210F 57.2
cSt Vis. @ 100C 9.41
Flashpoint in F 400 should be >365
Fuel % <0.5 should be <2.0
Antifreeze % POS should be 0.0
Water % 0.0 should be <0.1
Insolubles % 0.2 should be <0.6
TBN 4.4

Comments flagged the potassium and copper as antifreeze leak possible head gasket or intake gasket. Do another UOA in 2500 miles. Filtration is good

I notice no drop in antifreeze level.

With K that high and a positive for coolant, that sucks. You could do another run and check again....maybe try the GM Coolant tabs. Something slow won't necessarily be picked up in a coolant pressure test, but worth a shot.

Alas, the famous 4.3 intake gasket leak.....Better get that fixed ASAP! Mine fell victim at only 33,000 miles.

My mom's needed it at 50k on her '03 3.1, definitely get that taken care of.

Sad..

My 1996 c1500 truck is over 200k and never a problem. Was the 96 4.3 V6 a problem back then?

I agree with the others, you need to get it fixed and until you do, get the cheapest oil and change often. (after the repair, I'd do at least a few short OCIs to get rid of the garbage from the repair)

Bill

Bill, 4.3's with throttle body injection didn't have the problem. They run forever.

Is there a way to tell if it's an intake gasket leak or a head gasket leak?

I can say with 99.9% certainty it's the intake gaskets. Fel Pro make a replacement gasket that if installed correctly will never leak again.

The 96 4.3 is well known for this problem. I managed to make it to 137,000 before mine went. If you fix it your self it's not too costly,about $60 bucks. Most shops want 800 to 1000. It does take all day.

been there done that.I also didn't notice any coolant missing.

its a known problem w/lower intake manifold(LIM) gasket if you get on any of the s-series BBS's you'll find quite a few posts on it. GM has chosen not to deal w/it,no pun intended. I bought mine off e-bay for less than Summit wanted w/shipping. s-10 link w/pics of parts.

Good. I sold my truck to a good friend and he is still driving it daily with no problems.

I was going to get a UOA done on it to see if he has a problem starting. (I know catching it early helps)

Knowing this guy, he will drive the truck till he passes. He loves it and the truck is doing him well.

Thanks! bill

Thanks everyone. I will replace the intake manifold gasket and see how it goes.

It's really sad, REALLY sad; EVERY single GM vehicle we've had has had a leaky intake gasket. Even lost a 4.3L because of it; failed so bad the crankcase was full to the brim with antifreeze.

3.1, 3.4, 3.8, 4.3, 5.0, 5.7, and 7.4L motors from early 90s till about 2005 will ALL leak, PERIOD, end of story.

What a joke. Now you know why I'm so turned off by GM. Even if they have fixed the problem today, the fact they took a blind eye to the issue for 15 years and basically gave their loyal customers the middle finger speaks volumes. GM and it's dealers don't give a rat's patooot about their customers. Never again. Never again.

So true.