Finding internal coolant leak

[ktraver97ss]

I mentioned it in another thread, but I found coolant in the oil of my silverado. It is a 2002 with the 5.3L and 150k. What is the best way to find out where its coming from? It drives fine, no CEL or anything. Im thinking the 2 options are water pump or head gaskets, yeah? No visible leaks on the exterior.

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[ktraver97ss]

Anyone care to point me in the right direction? Should I do a coolant system pressure test first?

 

[Turbocharged400sbc]

no, maybe

 

[Bob Kazamakis]

The tool is free to rent so might as well. When you have water coming out of your dipstick you know the test is complete.

 

[Turbocharged400sbc]

whats your leak rate? (how much ya add and how often?)

if its an internal leak the best option is to pressurize it and wait till the coolant level stops dropping and that will give you an indication of the leak elevation. at which point you can listen for a hiss and see if you can locate the leak point

 

[EineKatze]

I would be willing to bet you have either slightly degraded a gasket (most likely in the valley, as its common on these trucks) or you have something as simple as a small gouge in a coolant passage allowing the coolant to sneak past. As 400sbc said, pressurize the sucker and see what you get. If you coolant level drops drastically you have blown through a gasket, if it trickles down I'd check your mating surfaces for imperfections. Hope this helps, now time to look for some info on preferred tubular k members...

 

[Bob Kazamakis]

You could do a compression test too and see if you've got a dead cylinder/bubbles coming out of your cooling. Spark plug condition would help too

 

[ktraver97ss]

Not sure, very slow, as the coolant reservoir was barely low and the last time i filled it was when a flush was done about a year ago.

 

[ktraver97ss]

What should i look for on the plugs?

 

[Bob Kazamakis]

If its not leaking very much chances are its probably not the head gaskets then. I'd start with the coolant pressure tester first. Easiest first

 

[ktraver97ss]

OK ill change the oil and see how much is in there and test the pressure on Saturday. Thanks guys.

 

[PANDA]

u just see some coolant looking stuff under the oil cap or dip stick?

 

[ktraver97ss]

Yep, oil cap.

 

[C.Evans]

That's condensation......

 

[PANDA]

My GTP had the same issue before, in the winter. I'm like oh shit I got problems. James said it was just because of the fluctuating temperatures causing moisture to form at the cap. I changed the oil anyway and it was perfectly clean...

 

[ktraver97ss]

I dunno, i have never seen this much and the same color as the coolant. It was down in the filler neck as well. Ill take a closer look and change the oil before anything else.

 

[Bob Kazamakis]

By "found coolant in the oil" I assumed you had already drained it!

 

[ktraver97ss]

Guess I should have specified, the low oil level light popped on and when i went to top it off, until i can change it, I saw it on the cap and neck.

 

[Wild White Pony]

If it's just in the valve cover I wouldn't sweat it. If you have cream in the oil pan start sweating. My valve cover and filler neck has the condensation puss all the time, but I have no water in the pan and the oil is clean. Can you show us a pick of the oil on the dipstick?

 

[Bob Kazamakis]

Well hopefully the panda is right and your oil is just oil

 

[PANDA]

I dunno, i have never seen this much and the same color as the coolant. It was down in the filler neck as well. Ill take a closer look and change the oil before anything else.

My dads durango had the same issue as you explained also in the winter. This was MUCH worse then the picture I just posted. It looked like someone yacked a pound of green barf down the oil fill. I have pictures just not here. Also normal apparently. The same shit was also all in the PCV lines.

 

[ktraver97ss]

No pics, trucks at home. Weird I would not have noticed it before. Hopefully im a jackass and that is all it is.

 

[ldyzluvdis06]

My GTP had the same issue before, in the winter. I'm like oh shit I got problems. James said it was just because of the fluctuating temperatures causing moisture to form at the cap. I changed the oil anyway and it was perfectly clean...

x2...i had the same issue happen once. just change the oil and see what's going on there.

 

[ktraver97ss]

Fucking junk GMs, shoulda bought a Ford.

j/k

 

[Turbocharged400sbc]

condensation

the low coolant is probably from evaporation