dirty oil Leak
Joined: Aug 2013
Posts: 4,806
Likes: 905
From: MICHIGAN
Car: 1988 Trans Am
Engine: L03
Transmission: 700R4
Axle/Gears: 10 Bolt 2.73 Open
Joined: Apr 2000
Posts: 1,533
Likes: 322
From: South Windsor, CT
Car: '89 GTA
Engine: ZZ6TPI
Transmission: T56
Axle/Gears: Borg Warner 3.70:1
Re: dirty oil Leak
The crust around the intake manifold to head connection looks a lot like dried coolant. Could be an intake gasket or thermostat gasket. Do you have dexcool (red/orange) coolant or plain old green?
Trending Topics
Re: dirty oil Leak
Thats next job on the list to drain and flush the coolant as the header tank looks like the coolant aint been changed in a long while (it looks quite sludgy) , tho temps on the car have been fine and heater runs well
Supreme Member




Joined: Feb 2021
Posts: 1,207
Likes: 448
From: WA
Car: 1989 IROC-Z
Engine: L98 350 TPI
Transmission: 700R4
Axle/Gears: BW 9 Bolt / 2.77 Posi
Re: dirty oil Leak
You need to identify that fluid. If it's coolant, you've got a leaking thermostat gasket, or leaking intake manifold gasket. Would be a shame to do a flush, then flush again to replace the gaskets. A pressure test would tell you for sure, or get the engine to full hot and have a real close look.
Joined: Apr 2000
Posts: 1,533
Likes: 322
From: South Windsor, CT
Car: '89 GTA
Engine: ZZ6TPI
Transmission: T56
Axle/Gears: Borg Warner 3.70:1
Re: dirty oil Leak
If your coolant is dark and sludgy, it needs to be flushed. If standard (green) and Dexcool (red) were mixed, it makes a brown sludgy mess. I would do a flush kit with straight water until you get it all out. Then, drain the radiator and block, fix the intake and thermostat gaskets (if that is in fact the leak), replace the thermostat and refill with 50/50 mix of coolant and distilled water.
Member

Joined: Jul 2014
Posts: 117
Likes: 5
From: Albany, NY
Car: 1987 Trans Am
Engine: LG4 305
Transmission: 700R4
Re: dirty oil Leak
I get oil (100% verified it's oil) that pools up in the exact same spot. I've been told the intake manifold (or maybe the valley cover) isn't torqued on tight enough so the oil splashes up there under normal operation. I've never bothered fixing it in the four years I've owned my car, I just wipe it up every once in a while.
Re: dirty oil Leak
I get oil (100% verified it's oil) that pools up in the exact same spot. I've been told the intake manifold (or maybe the valley cover) isn't torqued on tight enough so the oil splashes up there under normal operation. I've never bothered fixing it in the four years I've owned my car, I just wipe it up every once in a while.
Think you are dead right I aint had time to dig any deeper yet but what I wiped off was defiantly oil and I think it had a small amount in that place when I bought the car, since wiping it away nothing has come back yet so looks like a slow leak what ever it is. So a job for some time this summer.
Supreme Member




Joined: Jul 2006
Posts: 2,861
Likes: 785
From: 212 is up in this Bit@#
Car: Resto-Mod 1987 IROC-Z Clone
Engine: Alky fed L92 Vortec Twin-Turbo 6.8L
Transmission: My own built/ design 4L80M
Axle/Gears: Custom 12 bolt (4.10:1)
Re: dirty oil Leak
The Viscosity of that fluid tells me that I am not looking at Oil.
Also Dexcool dries and oxidizes in a particular way which looks like the Fluid in the Images.
Also Dexcool dries and oxidizes in a particular way which looks like the Fluid in the Images.
Joined: Sep 2005
Posts: 27,871
Likes: 2,429
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: dirty oil Leak
Yup. Looking at all that crusty GOOK around the coolant port of the intake manifold, somebody EFFFFFED UP and put Dex-Cool in it A LONG TIME AGO; and it's been oozing out of that gasket and around that bolt, as Dex-Cool always will since that kind of gasket is incapable of containing Dex-Cool, and some has been drying into that crust and some has been dripping off into that lovely pool.
Dex-Cool is GREAT stuff. I like it ALOT. Unfortunately however, its molecules are VERY small, and they go RIGHT THROUGH paper gaskets such as the 1955 design small block Chevy has, even more so than the water does. It's a SEVERE mismatch to these motors. Wonderful for a motor that's designed for it (aluminum-plate or plastic gaskets with silicone rubber O-rings, for example) around EVERY coolant port; UTTER FAIL for a motor with paper gaskets. Wrong application for the product.
My advice would be, remove the manifold and replace the gasket. Then CAREFULLY AND COMPLETELY drain & flush the radiator, the block by removing the thermostat and block drain plugs, and the heater core by removing the hoses and forcing water through it, to get EVERY TRACE of Dex out of everything; then fill it back up with DISTILLED water (NOT tap, NOT RO filtered) and old-skool green coolant, between 50/50 and 70/30 water to AF, depending on your location. Might also want to do away with those stoooooopid Torx head bolts, once you manage to get them out. I'd suggest regular hex-head stainless. 3/8"-16, 1¼" long. Lowe's has the best stainless collection among places of that general sort.
Dex-Cool is GREAT stuff. I like it ALOT. Unfortunately however, its molecules are VERY small, and they go RIGHT THROUGH paper gaskets such as the 1955 design small block Chevy has, even more so than the water does. It's a SEVERE mismatch to these motors. Wonderful for a motor that's designed for it (aluminum-plate or plastic gaskets with silicone rubber O-rings, for example) around EVERY coolant port; UTTER FAIL for a motor with paper gaskets. Wrong application for the product.
My advice would be, remove the manifold and replace the gasket. Then CAREFULLY AND COMPLETELY drain & flush the radiator, the block by removing the thermostat and block drain plugs, and the heater core by removing the hoses and forcing water through it, to get EVERY TRACE of Dex out of everything; then fill it back up with DISTILLED water (NOT tap, NOT RO filtered) and old-skool green coolant, between 50/50 and 70/30 water to AF, depending on your location. Might also want to do away with those stoooooopid Torx head bolts, once you manage to get them out. I'd suggest regular hex-head stainless. 3/8"-16, 1¼" long. Lowe's has the best stainless collection among places of that general sort.
Thread
Thread Starter
Forum
Replies
Last Post







