Specific signs of GM intake gasket leak

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To recap my recent coolant-in-oil "mystery", UOA indicated coolant in the oil from my 1999 Suburban 454 but the mechanic I took the truck to could not find (or did not recognize) any signs of the common intake gasket problem. Also did not find signs of head gasket failure. Cooling system pressure test passed. So my plan is to drive it normally (which is very little) for a while and sample again after maybe 500 or 1000 miles (which probably means 6 months). Obviously I want to keep an eye on things in the mean time. I'll keep an eye out for milky oil, and monitor the coolant level and see if it goes down, but I wanted to know exactly what I should look for with respect to the intake gasket. The mechanic told me I should look for coolant residue on the front of the engine around the bottom of the intake. Will they always show externally when there's a leak? To be honest the engine is pretty grimy so it's not even going to be extremely easy to see coolant residue. Is there anything else I should be keeping an eye on?
 
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 Originally Posted By: rationull
The mechanic told me I should look for coolant residue on the front of the engine around the bottom of the intake. Will they always show externally when there's a leak? To be honest the engine is pretty grimy so it's not even going to be extremely easy to see coolant residue.
Wash the engine? I'd stick with milky looking stuff on the oil cap as your best indicator.
 

rationull

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 Originally Posted By: mstrjon32
Wash the engine? I'd stick with milky looking stuff on the oil cap as your best indicator.
Washing it is the obvious option. The grime is thick though, so assuming I get off my lazy butt and wash it, it's going to take a while. I doubt the previous owners ever washed the engine bay and to be honest I'm not exactly a compulsive engine washer myself. The oil cap doesn't have any milky sludge or anything abnormal on it, despite the fact that it's at the end of a fairly long pipe coming up from the engine. I'll keep an eye on it.
 
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Those DIY car wash with the wands, if done carefully, works well for cleaning engines. I use the cheap engine cleaner (exterior) from Wal-mart. Just keep the spray away from electrical stuff the best you can.
 
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I'd be weary of using those DIY car wash for cleaning engines. read some stories about electrical components going bad
 
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Just be careful about getting the nozzle close to the electrical bits and you'll be fine. Past experience of a few of my friends suggests that you cover the alternator with a plastic bag. I bought a couple of cans of some cheap engine degreaser and soaked the engine and transmission of my '74 Beetle, which was caked with years and years of oil and transmission fluid. Came suprisingly clean at the coin-op car wash.
 
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 Originally Posted By: dwendt44
Those DIY car wash with the wands, if done carefully, works well for cleaning engines. I use the cheap engine cleaner (exterior) from Wal-mart. Just keep the spray away from electrical stuff the best you can.
\:\!
 
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