oil in the overflow coolant tank

[jimbo98]

I have just started seeing oily gunk on the sides of the overflow tank. Is this terminal? There is oil on the radiator cap also but the oil is staying clear. I change it every 3k miles. Obviously, something is letting go inside the block. With 135K on it im expecting to overhaul it. But was hoping for for a little more time. Anyone ever rode this problem till it blew?

 

[bsamoul]

Well, oil in the radiator will cause it to just overheat so you'd better just change it fast

 

[96ProCompTahoe]

are you still using dexcool? and have you ever replaced your radiator cap?

if you haven't it may be letting air into your system, thus your gunky build up from the dexcool's "lubricant"

75% of the 100 or so tahoes i looked at before i bought mine either had the green antifreeze put in it, (big no no) or the oily crap build up in the overflow bottle and top of the radiator.

 

[jimbo98]

oil in coolant tank

Okay, i still have the dexcool in there. I will flush the coolant system and put some new in. Can I test my radiator cap or just buy a new one? How can I get all the air out of the system after flushing? Anyone know the procedure for this? Maybe there is hope for my old motor.

 

[swirvdawg]

135k expecting to overhaul it. Whats wrong with you people at 135k its still has lots of life left if taken care of.

 

[jimbo98]

oil in coolant tank

ive seen too many tahoes with new motors at less than my 135K. I bought mine with 114K so the history of it is unknown. But yes it might have a lot of life left in it i hope.

 

[96ProCompTahoe]

IIRC you just fill it up and run it without the radiator cap on it, it lets all the air out of the system.


mines got 167K on it and still going real strong. few parts have been replaced since i've got it but nothing major.

alternator, tensioner, fan clutch, belt. (the alternator and tensioner were replaced when the squeak turned out to be the fan clutch, but the alternator needed replaced with the new system anyway)

then of course, headers and the CIA.

 

[blk87brd]

I put close to 240K on my 99 tahoe 5.7 without doing the engine with only a slight lose of oil pressure and compression with in 10lbs. I guess there are lemons in anything but they are few and far between in these excellent engines.

 

[hoser]

Have you checked your oil level to verify its NOT engine oil in the coolant?

I have been reading about the GM coolant since it came out, more trouble than its worth IMO, its a knee jerk reaction to something more environment friendly and were the guinea pigs, I would do a system clean and flush (requires removing the block drain plugs one is the knock sensor) then going to the old green coolant.

 

[treepete]

man... I thought maybe intake gasket got so bad, that engine oil was showing up in the coolant.. I hope not, but arent those the symptoms?

96, you can solve that fan clutch squeak with electric perma cools.

 

[96ProCompTahoe]

96, you can solve that fan clutch squeak with electric perma cools.

dude i know, they are on the list. haha. gotta pay down the locker and new gears, and hopefully that rear disc kit if all goes well.

o yeah, and the big 3 upgrade, new water pump and exchange the alternator again.


one of these days. one of these days.

 

[treepete]

dude. Ill send you the blob of extra wire I have and the rockford fosgate connectors if you like ( for the big 3)

man, wait on the brakes... fans free up waay more HP than youll need for brakes.. well, I actually cant say that cause I dont know about that whole off roadin thing you do. and the locker and all that is so new, I cant speak to it.
LMK about that stuff.
PEte

 

[96ProCompTahoe]

i will defently take the wire and connectors. just send me a PM with the details and how much you want for it.

ah after it gets regeared tues/wed its gonna feel like i added a hell of alot of HP to it anyway. the brakes are top priority since its time for new pads front and rear. sooo new stainless rear brake line to match the fronts, hopefully some new slotted and/or cross drilled rotors, and hopefully be getting the kit for the rear disc conversion.

 

[treepete]

I'm just drinkin' is all. heres what I mean...

 

[treepete]

as you can see, they get many miles getting rolled down the driveway. the passenger side of the silverado is, like, totally, missing.