My mom found oil in my car's radiator.

Hello there I have a question my mom found oil in my car's radiator. I need some help with this problem.

...usually a head gasket leak, sometimes a bad intake manifold issue. Cause must be determined and fixed ASAP (like, today) because if it is not fixed immediately and gets worse then engine catastrophic failure is (kind of) likely.

A compression test in which one or more cylinders tests under spec signals a bad gasket, usually. I think low is 100PSI but DONT quote me and hopefully someone who has specs will chime in (I don't have my manuals ATM).

The normally-aspirated cars 1995-1999 had plastic intake manifolds that leaked especially if the coolant was not maintained. See http://www.ebay.com/gds/GM-3800-Series-II-Coolant-In-Oil-not-head-gasket-/10000000003710578/g.html; if you have to replace the head gasket you need to service the intake manifold anyway. As for the head gasket see http://troubleshootmyvehicle.com/gm/3.8L/how-to-test-a-blown-head-gasket-1.

Finally be sure the oil was not in the coolant for some dumb accidental reason.

Curious as to how your mom came to be poking around the radiator cap on your car.

When I started the rehab on my Riv, I had oil film under the cap and the coolant reservoir was nasty. I did what I could to get the oil off the top of the fluid and scrubbed out the reservoir. Next was a treatment of Bar's Leaks Powder Radiator Stop Leak. I know that this isn't magic mechanic but I haven't had oil since.

On a side note, I have a Ford F-150. The manual lists a radiator leak additive. It was a WTF moment when I read that.

IFallsRon wrote:

Curious as to how your mom came to be poking around the radiator cap on your car.

When I started the rehab on my Riv, I had oil film under the cap and the coolant reservoir was nasty. I did what I could to get the oil off the top of the fluid and scrubbed out the reservoir. Next was a treatment of Bar's Leaks Powder Radiator Stop Leak. I know that this isn't magic mechanic but I haven't had oil since.

On a side note, I have a Ford F-150. The manual lists a radiator leak additive. It was a WTF moment when I read that.

This got me thinking: when a GM dealer does a flush-and-fill on a car with 3800 engine, part of the work (per the manual) is to put a few stop-leak tablets in the radiator. This is in the factory service manual. If someone replaced coolant in your car without consulting the manual, they likely did not use any stop-leak. Dealers sell the tabs cheaply; WalMart even cheaper.

Yes, the problem might be that simple to fix.

Albertj

We do not use tablets anymore. The FSM's are out-dated.

Most common cause of oil in the coolant is an LIM leak. It isn't THAT big of a deal unless the opposite is happening.....coolant in the oil. Either way, it needs to be repaired.

my old engine exploded five years ago, I do agree it might be a gasket leak, had my engine replace and when we just recently check the inside of the radiator there even older oil. Before the found the coolants looks really clean, and not a mixed of oil, when the coolant is gone, there old old oil inside the walls of radiator and the weird metal thing inside.

I had not use my car, for 2 week now.

So the engine is safe and the engine is fine too.

Abaddon wrote:

We do not use tablets anymore. The FSM's are out-dated.

Most common cause of oil in the coolant is an LIM leak. It isn't THAT big of a deal unless the opposite is happening.....coolant in the oil. Either way, it needs to be repaired.

I admit I have still used the tablets - I only flush-fill every 100-150K - and it will be a while before I have to do it again. So... what's done instead of the tablets?

Albertj

The factory puts tablets in when they assemble the car....maybe. We don't know. There are no more tablets to be used during repairs at all. It isn't listed in our service procedures any longer, and I don't even think the parts dept has them either.

Rachel, the problem needs to be taken care of. To say that your engine is "fine" is being a bit nice. That internal leak is going to get worse. Once the coolant starts mixing with the oil (which it will eventually), the engine will be toast soon after.
A little oil in the coolant won't hurt anything, but get coolant into the cylinders, and it'll start eating bearings and such.

Abaddon wrote:

The factory puts tablets in when they assemble the car....maybe. We don't know. There are no more tablets to be used during repairs at all. It isn't listed in our service procedures any longer, and I don't even think the parts dept has them either.

Rachel, the problem needs to be taken care of. To say that your engine is "fine" is being a bit nice. That internal leak is going to get worse. Once the coolant starts mixing with the oil (which it will eventually), the engine will be toast soon after.
A little oil in the coolant won't hurt anything, but get coolant into the cylinders, and it'll start eating bearings and such.

Various people have the tabs NOS (see http://www.jegs.com/i/ACDelco/065/10-108/10002/-1) and they are still made (http://barsleaks.com/product/radiator-stop-leak-tablets/). I am disappointed but not surprised they did not keep them on the BOM for repairs, as the problems that you have if you don't use them don't show up immediately--I imagine that will become an issue because the block porosity issues did not all of a sudden go away.

Other stop-leaks will work for block porosity and pinholes in metal: ground black pepper (yes the grocery store kind) or ground ginger (yes, again, the grocery store kind) can work. The stop-leak tabs are ground ginger and ground walnut shells (look at the MSDS *real* carefully) and work more consistently than the foodstuffs. There are also stop-leaks with aluminum powder.

As Abaddon says -- fix it as soon as possible. No good can come of letting it go.