Yellowish condensation under oil cap + low coolant warning

[Potch]

Hi everyone.

I got a low coolant warning on my message center a little over a week ago now. When I checked the reservoir it was a little under the full cold line so I topped it off with 1 liter of dexcool/water mix.

Before taking a short road trip to see family, I checked coolant and oil levels and saw there was some condensation with a yellowish color under my oil fill cap. I thought it looked like I might have coolant in my oil but wanted to reach out to the community for advice.


I did some research and it doesn't appear I have the Gastech heads that are prone to cracking, but I'm just going off of the # on the head not matching up with what I read to be the bad ones. My vehicle does fall into the year/vin/engine that the TSB (#06-06-01-019B) on the subject covers.

I've had the vehicle for almost 1 year and it has been running like a champ. No fluctuations in operating temp and what I read to be normal fluctuations in oil pressure in accordance with RPMs. At my last oil change I put in Mobil1 full synthetic high mileage 5W-30.


Any advice or personal experience on the subject is greatly appreciated!


2002 Tahoe LS, 4wd
5.3 L Vortec

Edit: I'm at 137.7 k miles. 6.6 k of which were in the last year.

 

[Scottydoggs]

its nothing to worry about, its condensation from inside the engine. my regal gets a booger looking yellow snot slug around the inside of the cap every winter. wipe it out carry on.

 

[Potch]

its nothing to worry about, its condensation from inside the engine. my regal gets a booger looking yellow snot slug around the inside of the cap every winter. wipe it out carry on.

That makes me feel a lot better. Thanks!

 

[Doubeleive]

my experience was mine was drinking about a quart every 2 weeks and my cap looked slightly better than yours, that was at 264k, it wasn't leaking and it ran fine, it was just thirsty, I ended up getting the vehicle stolen shortly thereafter thru my own stupidity got it back about 3 days later, so I called my insurance company and said "hey they ruined my engine" the adjuster came out popped my oil fill cap off (it looked almost like yours) and they paid me $1890.00 for a rebuilt engine of which I kicked in a little more and got a brand new crate motor, was it illegal>? maybe-sue me. lol

 

[iamdub]

If you drive a lot of short trips (5 miles or so), the engine can build up a lot of moisture on the inside which can make the oil look like that. This is not to say you don't have a small coolant leak somewhere, but it's probably too small to find at this point and may not even be internal. Fill the reservoir to the line and clean the cap and keep an eye on it. You'll have to purposefully take 10+ mile drives once or twice a week to burn off condensation if you're a short-tripper.

 

[Potch]

If you drive a lot of short trips (5 miles or so), the engine can build up a lot of moisture on the inside which can make the oil look like that. This is not to say you don't have a small coolant leak somewhere, but it's probably too small to find at this point and may not even be internal. Fill the reservoir to the line and clean the cap and keep an eye on it. You'll have to purposefully take 10+ mile drives once or twice a week to burn off condensation if you're a short-tripper.

I do mostly take short trips. I live 4 miles from work and just about everywhere I go in town is within 5 or 6.

Thanks for your comment!

 

[iamdub]

I do mostly take short trips. I live 4 miles from work and just about everywhere I go in town is within 5 or 6.

Thanks for your comment!

Well, this pretty much confirms the cause of your problem. Better than a blown head gasket! You gotta drive that thing more or it's lifespan will be shorter than it should be.

 

[HiHoeSilver]

Well, this pretty much confirms the cause of your problem. Better than a blown head gasket! You gotta drive that thing more or it's lifespan will be shorter than it should be.

Agreed. Go out and get that bad boy hot every so often! Will be good for da bote a yas.

 

[kf7grq]

The simple thing to do is have your mech put a Stantz coolant pressure tester on you rig. You will know almost instantly if the issue is a blown head gasket or a cracked block/head. While they are at it, they can also give you radiator cap a quick check.

Most respectfully
Michael

 

[Potch]

Thanks for the comments guys!

Go out and get that bad boy hot every so often!

My truck does usually get up to operating temp by the time I get to work if that makes any difference.

Also, about once a month I take a ~175 mile trip to see family and when it's warmer I like to take longer trips out to the lake or the woods for some fishing or camping.