Need cheap test for coolant in oil.

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Aug 20, 2003
I have an 01 3.1L Chevy motor and I am concerned about all the information in regards to the leaking intake manifold gaskets. I would like to know if there is an inexspensive test for checking for coolant contamination in the oil? I use Pennzoil 5w-30 and Wix oil filters every 3-4k since new and have seen no sign of coolant on the dipstick or under the oil cap. I just dont want to find out right after the warranty is up that I should have had the dealer change the gaskets. The motor has 31k trouble free miles on it right now and warranty is up at the end of this May.
Thanks for any info!
You are probably still safe at only 31K miles, my intake gaskets in my '97 3100 didn't start to go until 114K, and didn't start mixing coolant into the oil until 120K when I finally got it fixed.
Mine just went with only 38K miles. Although it is a '97, GM is taking care of it due to low mileage. The cheapest and most effective test IMO is to have your cooling system pressure tested; do that as soon as you see any signs of losing coolant, or in your case before the warranty expires. In my case I noticed the poop tank level was low so I went for the test ($25) when they performed the steering recall.

You can buy a pressure tester and DIY but it's probably cheaper to take the car to a shop, only takes a few minutes.

[ February 24, 2004, 03:44 PM: Message edited by: Pluto5 ]
$20 for oil analysis of a sample you remove during an oil change is a cheap and easy way to go. I use and found a leaking intake on our '02 Oldsmobile by having the analysis done on every oil change starting at 30,000 miles. Our leak showed up at 41,000 miles.

With these engines I would consider bi-annual oil analysis a neccessary precaution.

No offense but why wait for the results of an oil analysis to find out if your coolant leaks when you can tell immediately with a pressure test?

Also, the cost of bi-annual oil analysis costs more than twice my 4 mo OCI with S-T oil and filter.
Try the frying pan test. Drop some motor oil from the dipstick in a hot frying pan, if it boils, its got water in it.

Water/coolant boils at 265F or whatever, UNDER PRESSURE. Less at sea level pressure.

Dino oil at what, 365F? Syn >400F?

Don't let your wife catch you.
You can use a pop can cut in half or an old spoon. You can use sterno, torch, or any heat source. One drop of oil on the hot spoon will give you a good idea. Crakeling and spitting is watter!
A pressure test will not always show if you have a leak. After oil analysis found coolant in the oil of my 98 chevy truck with the 5.7L, I took it to the dealer to have the coolant system pressure tested and they told me it tested fine. I told them about the oil analysis and they said that the leak could still be small enough that a pressure test would not show anything.

Also the test should be done when the engine and system is cold as this is when most internal leaks occur. Sometimes when the engine is hot, the leak will temporarily seal itself.

I ended up having my intake manifold gaskets replaced and you could clearly see on the gaskets where it had been leaking.

Some other signs to look for is condensation buildup on the underside of the oil filler cap. I started getting this on mine and my overflow tank level was going down. Just by looking at the oil, you would never have been able to tell I had a leak because the oil always looked clean and normal.

Get an oil analysis done as I think this is probably one of the best ways to determine if you have an internal coolant leak.


Originally posted by JohnBrowning:
You can use a pop can cut in half or an old spoon. You can use sterno, torch, or any heat source. One drop of oil on the hot spoon will give you a good idea. Crakeling and spitting is watter!

I heard you can also do this by dripping a couple drops on the hot exhaust manifold.
Oil analysis showed signs of coolant getting into the oil on our '02 Silhoette very early on, well before a radiator pressure test showed it. The radiator pressure test happens with the engine cooled down and off. Such a test find big leaks, but can easily miss small ones.

Of all the readily available methods, the oil test at $20 is by far the most sensitive affordable test.

Finally, you want to find sodium or other traces of antifreeze well BEFORE there is measureable water in the oil and certainly before any of the backyard detection methods will show the water.

The idea is to find the problem as early as possible before secondary damage occurs. The manifold gasket job is $800-$1000 while a new engine is around $5,000.


[ February 25, 2004, 11:39 AM: Message edited by: jthorner ]
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