I know this isnt really a J-body engine but I know some people on here put the 3100 top end on there 3.1 so sombody must know something about it.
My Uncle has a 3100 and he dosent know anything about cars and he took his car in to get his oil changed and was told he was getting antifreeze in his oil cause his intake manifold gaskets were leaking and he wanted $800 CAD to replace the intake gaskets.
I havent even looked at the car yet but I know you cant get antifreeze in your oil because of a intake gasket being gone, I think its a head gasket. My question is are the intake manifolds on the 3100 cooled by antifreeze or something, and he also said the same thing was happening to his friends car with a 3100, so is there any common reason for a 3100 to get antifreeze in the oil?
I'm going over there later on to check the oil and do a compression test.
Any help apreciated.

hey what's up tyrin. glad to see you around again.

that doesn't sound right at all.



Originality and Creativity surpasses Popularity

ALL 3100 and 3400 engines have a fault with the intake gaskets....they go bad and can be costly to fix....i suggest a professional on this, in pro shops it takes up to 8 hours for one set

So would it be gas in the oil then, not antifreeze like he said. I still havent seen it so I wouldnt know. And is the intake manifold cooled by antifreeze?

Quote:

i suggest a professional on this

Professional, lol I never take anything to them I do it all myself, I know it's going to take a hole day but its a lot better than paying $800. Dos anyone know roughly what he would expect to pay for the gaskets?
thanks

yea lower intakes on them had gasket problems. yes there is coolant in the intake manifold, all gm v6 engines do. the gasket develops a leak around the water passage between the head and intake. usualy it will just leak out onto the tranny, but they have been know to leak into the oil.

It's not too hard to replace the Lower IM. You can do it.



1991 3.1L V6 Sunbird LE
15.365@88.52
Full Interior...3-Speed Automatic.

Satisfied Customer of:
POWERSHOP PORTING SERVICE

i wouldnt pay someone to do it. just change the intake manifold gaskets. all done in aan afternoon with hand tools.


.

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"What are we going to do tonight?"
"The same thing we do every night, try to make the SVC go faster!"

it cost about 70-80 in parts US- about 60 for the gasket set, a few dollars for the RTV sealant, and a few bucks for some coolant. and while you're in there, may as well change the thermostat. I've done a couple of these jobs, they aren't bad. I'm actually doing one tomm for a guy I know. I charge 400 to do it. don't forget to change the oil after you get everything sealed back up- before you run it.

Please make sure to buy your new 3100 gaskets from GM.
Gm redesigned the gaskets in late 02 to help battle the leakage problem

they put metal inserts around the horizontal lower intake bolts to allow the bolt to be torqued tighter to prevent leakage.

oem replacements (like felpro) have yet to follow suit. they will leak again.

the gaskets from Gm are approx 70 cdn.

book time for changing the intake gaskets is approx 5.5 hours (less in cars like Malibu and grand am (n bodies) and more in the vans) but many Gm techs can do it in well under 3 hours.

it is a fairly straight forward process. just take your time.



___________________________________________
1989 3.1/3400 hybrid Nitrous fed Z24.
14.13@96.69 mph full interior, N/A
(still haven't sprayed at the track)

i just got mine changed a while ago useing FELPRO gaskets, hopfully they last me a good while. at least untill i start smoe engine work. I'll look into the GM gaskets when i do.
thanks.

Mr.Efficiency (Tyrin) wrote:So would it be gas in the oil then, not antifreeze like he said. I still havent seen it so I wouldnt know. And is the intake manifold cooled by antifreeze?

LOL No, It would be Coolant into the oil, As stated the 3X00's are terrible for this leak. The intake manifold gasket cracks at the coolant passage location, (coolant flows through the manifold. Look at the placement of the thermostat on a Lower. The coolant has two places to go, Out the side of the block, Or IN the engine and into the oil.

If your uncle doesnt get this fixed he will be doing more than an intake gasket. Ive seen many a camshaft snapped in half due to the coolant ruining the #4 cam bearing and causing it to seize there thus snapping it in half.
I have seen heaps of customers who left them too long and ruined the main/rod bearings causing rod knock.

Daily, The 3100 gaskets have never recieved the "update" with the metal tabs. Only the 3400 gaskets have these.


Colin, 92 sunbird GT
3200 high output. Naturally Asperated.
14.391 @ 96.479, 2.134 60 foot. Street Tyres.
13.99 @ 95.22, 1.92 60 foot on Slicks.
Engineered Performance LSD equiped.
http://www.domesticcrew.com/colin/
Member of the www.turboz24.com crew.

Colin.. what about 2000+ 3100's? he never mentioned the year



___________________________________________
1989 3.1/3400 hybrid Nitrous fed Z24.
14.13@96.69 mph full interior, N/A
(still haven't sprayed at the track)

Use #11588914 and #11588915 intake manifold bolts as per latest bulletin.