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Oil in coolant. Lean rougg idle

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MarkJamesGN22

New Member
Joined
Apr 25, 2023
Messages
14
Hi everyone, my car is running great under boost I'm running E85 22lbs of boost. 11.0:1 AFR. No knock. Runs super strong. My only problem is I see traces of oil in the coolant overflow bottle( not a lot, just a slight amount on top) and seems to be pushing coolant out of the over flow bottle after a good hard run.

Absoluetly no coolant in the oil. While I was tuning this car before I did have a few backfires from ignition related problems which are now fixed. I have done a compression and leak down test and both were perfect. I also pressure tested cooling system and looked in cylinders for coolant with a borescope camera, and no coolant was found. When the car idles, it does have a rough idle. It shows 14:1-15:1 afr at open loop idle with TT chip. The idle is pretty rough most of the time. Is there any possibility that the intake manifold is blown and letting boost into the coolant and crankcase? Could it have blown from the backfires? I did have traces of oil around the oil filler tube after a high boost run. No smoke from exhaust at all.
 
You can buy an adaptor to put air pressure into the radiator cap and check for leaks. Prolly a head gasket needs replaced.
 

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You can buy an adaptor to put air pressure into the radiator cap and check for leaks. Prolly a head gasket needs replaced.
I have pressure tested it with a manual coolant pressure tester with all the spark plugs out and even looked inside each cylinder for traces of coolant. None. I have left the pressure tester on the car for hours and it doesn't drop pressure.
 
Have you done an oil analysis? That will show very small amounts of coolant in the oil. There needs to be alot of coolant in the oil for it to be visible on the dip stick or in the drain pan.

Blackstone Labratories is the one I use.

For example when I run above 32psi in my 86 GN my oil reports show a very small amount of coolant that zi cannot see or smell. Lower the boost and no more traces of coolant on the report.

I figured I found where the limits of the OEM head gaskets were and they were starting to weep or lift the head slightly. I would never have seen this without the oil analysis.
 
Have you done an oil analysis? That will show very small amounts of coolant in the oil. There needs to be alot of coolant in the oil for it to be visible on the dip stick or in the drain pan.

Blackstone Labratories is the one I use.

For example when I run above 32psi in my 86 GN my oil reports show a very small amount of coolant that zi cannot see or smell. Lower the boost and no more traces of coolant on the report.

I figured I found where the limits of the OEM head gaskets were and they were starting to weep or lift the head slightly. I would never have seen this without the oil analysis.
I did just get a kit from blackstone. I guess i will pony up and pay for the analysis. It cost more to check for coolant contamination, then just standard test right?
 
How is the interior of your radiator?

Are the internal trans & oil coolers still functional?
 
How is the interior of your radiator?

Are the internal trans & oil coolers still functional?
New aluminum radiator. I was gonna disconnect the engine oil cooler and clean out the reservoir. The insides of the radiator is clean. No oil in there just the overflow bottle. I am running rmi 25 with my coolant which is supposed to make all the crap go to the top. I have no overheating. Steady 175 degrees, 180 maybe in traffic.
 
engine oil pressure is higher than coolant pressure could have a leaky cooler in radiator
But it will push water in pan when shutoff because 15 lb cap can push coolant to engine when not running
Time for oil analogs and remove the cooling lines from radiator
 
I did just get a kit from blackstone. I guess i will pony up and pay for the analysis. It cost more to check for coolant contamination, then just standard test right?
I don't believe it cost additional, at least I have not been opting for anything but the standard test and coolant, when present was mentioned.
 
engine oil pressure is higher than coolant pressure could have a leaky cooler in radiator
But it will push water in pan when shutoff because 15 lb cap can push coolant to engine when not running
Time for oil analogs and remove the cooling lines from radiator
I will do that next. Thanks! Could it also cause the coolant to over flow after a high boost pull without overheating?
 
Hi everyone, my car is running great under boost I'm running E85 22lbs of boost. 11.0:1 AFR. No knock. Runs super strong. My only problem is I see traces of oil in the coolant overflow bottle( not a lot, just a slight amount on top) and seems to be pushing coolant out of the over flow bottle after a good hard run.

Absoluetly no coolant in the oil. While I was tuning this car before I did have a few backfires from ignition related problems which are now fixed. I have done a compression and leak down test and both were perfect. I also pressure tested cooling system and looked in cylinders for coolant with a borescope camera, and no coolant was found. When the car idles, it does have a rough idle. It shows 14:1-15:1 afr at open loop idle with TT chip. The idle is pretty rough most of the time. Is there any possibility that the intake manifold is blown and letting boost into the coolant and crankcase? Could it have blown from the backfires? I did have traces of oil around the oil filler tube after a high boost run. No smoke from exhaust at all.
I meant intake manifold gasket blown, not intake manifold.
 
May be residue due to the RMI-25

Siphon it off & see if it returns, along with the other suggested tests.
 
Hi everyone, my car is running great under boost I'm running E85 22lbs of boost. 11.0:1 AFR. No knock. Runs super strong. My only problem is I see traces of oil in the coolant overflow bottle( not a lot, just a slight amount on top) and seems to be pushing coolant out of the over flow bottle after a good hard run.

Absoluetly no coolant in the oil. While I was tuning this car before I did have a few backfires from ignition related problems which are now fixed. I have done a compression and leak down test and both were perfect. I also pressure tested cooling system and looked in cylinders for coolant with a borescope camera, and no coolant was found. When the car idles, it does have a rough idle. It shows 14:1-15:1 afr at open loop idle with TT chip. The idle is pretty rough most of the time. Is there any possibility that the intake manifold is blown and letting boost into the coolant and crankcase? Could it have blown from the backfires? I did have traces of oil around the oil filler tube after a high boost run. No smoke from exhaust at all.
I had a C-4 that did the same thing. I sold it with the issue disclosed, but after I found out if it had an oil cooler ( I don't know if it did), it is a trouble spot for oil into antifreeze, also as someone mentioned trans fluid getting in in the radiator.
 
Clean out overflow Disconnect the oil cooler run car for a couple of days see if problem recreates itself
Now on the 15 to 1 afr check vacuum lines for possible leak
Or adjust fuel table .
 
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