Coolant in the Oil Cap!!!
Coolant in the Oil Cap!!! Hello everyone,
i've been driving my car around now for a day or two, its first maiden voyage. I'm still at the monitoring stages and noticed that i had some coolant on the oil cap, i had just changed the oil and didn't notice any milk coming from the old oil. any ideas on what it could be? i checked the dipstick and the oil is still clean with no signs of coolant, no white smoke on start up and the coolant overflow was pretty much full. i did lose a little bit of coolant in the radiator but that may be due to me not fully bleeding the system. pretty stumped?!?! anyone have any ideas on this? i can't really drive it around that much because its still open headers and i've yet to get my exhaust fabbed up. Hope someone can help, its a 1999 LS1(n/a , bone stock) , Thanks!
i've been driving my car around now for a day or two, its first maiden voyage. I'm still at the monitoring stages and noticed that i had some coolant on the oil cap, i had just changed the oil and didn't notice any milk coming from the old oil. any ideas on what it could be? i checked the dipstick and the oil is still clean with no signs of coolant, no white smoke on start up and the coolant overflow was pretty much full. i did lose a little bit of coolant in the radiator but that may be due to me not fully bleeding the system. pretty stumped?!?! anyone have any ideas on this? i can't really drive it around that much because its still open headers and i've yet to get my exhaust fabbed up. Hope someone can help, its a 1999 LS1(n/a , bone stock) , Thanks!
TECH Regular
Joined: Sep 2008
Posts: 425
Likes: 1
From: Scottsdale, Arizona
yes, sometimes when it's cold out you will get some condensation, like if you would pull a valve cover you will see some moisture.
If you drain the oil and it doesn't look milky then you should be ok. But it's definately something to keep an eye on if you are concerned.
If you drain the oil and it doesn't look milky then you should be ok. But it's definately something to keep an eye on if you are concerned.
ahhh, i really hope that its condensation, but why does it smell so much like coolant?? and i'll take the blame for not letting it warm up, i was excited to drive it, hehe. My car doesnt have a pcv hooked up, the motor isnt in an f-body. Thanks for the replies everyone, i'll definitely keep an eye out!
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ahhh, i really hope that its condensation, but why does it smell so much like coolant?? and i'll take the blame for not letting it warm up, i was excited to drive it, hehe. My car doesnt have a pcv hooked up, the motor isnt in an f-body. Thanks for the replies everyone, i'll definitely keep an eye out!
You say you do not have a PCV system?? That is the reason you are getting this condensation in the oil cap. Are you at least running breather filters, or is the entire system closed off??
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Brett Foote
TECH Fanatic
Joined: Aug 2006
Posts: 1,407
Likes: 63
From: Knappa, Oregon
It's just condensation. Shows up more in the winter than in the summer. You may not think of there being air inside your engine, but there is. And went your engine cools off, the moisture in that air condenses out. The moisture in the engine ends up in the oil and will evaporate out after the engine gets good and warm. When you first start your car and you see fog rolling out the tail pipe that is the condensate from inside your exhaust and engine as things heat up. You can even see drips of water running out the exhaust sometimes.
Clean the oil cap and check it every couple days to see how big the issue is. Probably nothing.
Clean the oil cap and check it every couple days to see how big the issue is. Probably nothing.
i'll definitely keep an eye on things. yeah i have no pcv, where would i need to hook up breathers to? i believe its entirely closed off. now i have a new problem, went to start the car today and had a little snafu. heard an electrical "click" and lost all power to the car, the cars wired battery -> starter -> alternator -> engine bay fuse box. battery's still good but everything just got cut off, i'll have to crawl under and do a whole troubleshoot... irritating since i've been doing that for the past 5 months almost every minute of my free time 
I saw that yellow milky looking stuff on mine a few years ago and was concerned and then just realized it was condensation from the engine not running long enough in cold weather to completely burn it all off. I'm certain a 160* thermo makes it more prone to this too as it doesn't get as hot and doesn't heat up as fast after 160*. Just have to run it longer and make sure it gets nice and hot and it will burn that moisture off.
Sorry bout your new electrical problem...all the fuses good?
Sorry bout your new electrical problem...all the fuses good?
i'll definitely keep an eye on things. yeah i have no pcv, where would i need to hook up breathers to? i believe its entirely closed off. now i have a new problem, went to start the car today and had a little snafu. heard an electrical "click" and lost all power to the car, the cars wired battery -> starter -> alternator -> engine bay fuse box. battery's still good but everything just got cut off, i'll have to crawl under and do a whole troubleshoot... irritating since i've been doing that for the past 5 months almost every minute of my free time
You have 2 options, both will work:
The ideal option is to upgrade to an LS6/L92 valley cover with integrated PCV system. You will have to grind down a casting tab in the valley to allow it to fit, but its the best system available. It will vent crankcase vapors and condensation, without sucking up lots of oil like the stock system does. You can even run a catch can to prevent any oil buildup from entering the intake.
The other option is to run breather filters. You would have to put one on each valve cover, on the nipple where the stock PCV hoses would attach to. Its also not a bad idea to get an oil cap with a breather built onto the top of it to vent the gasses up front. The problem with this system is that it doesn't provide any vacuum on the crankcase, so not all the contaminants will be removed. However, the majority of condensation and oil vapors will escape through the breathers. The other downside is that it will smell pretty bad in the summer months when its hot. Every time you stop at a light with the windows down, you get a nice whiff of oil vapor
Running with a closed off system though is a VERY bad idea. You will blow out seals (front and rear mains, valve covers, ect), sludge will build up inside the engine, and your oil will not last long at all. Acids can build up in the crankcase as a byproduct of combustion, and they can eventually eat through soft aluminum bearings and seals. Its basically a fast way to destroy the insides of your motor.
Thanks for the reply Wesman, i'll get some breathers and run them on the valve covers. yeah the electrical problems is a freakin pain, i'll look at it today and keep you guys posted. hopefully the moisture is just condensation and nothing big to worry about, thanks for all of the help!
edit! found all my pcv stuff laying around and hooked it all up, should i still run a breather to this?
edit! found all my pcv stuff laying around and hooked it all up, should i still run a breather to this?
Thanks for the reply Wesman, i'll get some breathers and run them on the valve covers. yeah the electrical problems is a freakin pain, i'll look at it today and keep you guys posted. hopefully the moisture is just condensation and nothing big to worry about, thanks for all of the help!
edit! found all my pcv stuff laying around and hooked it all up, should i still run a breather to this?
edit! found all my pcv stuff laying around and hooked it all up, should i still run a breather to this?
sweet, i'm all squared away! the pcv is all routed and secured , i found my power problem and it was a false ground, weird because i drove with the same ground a handful of times, good thing it happened earlier than later. Thanks everyone ! i'll take it around the block a couple times tomorrow and see how it goes!
TECH Regular
Joined: Sep 2008
Posts: 425
Likes: 1
From: Scottsdale, Arizona
Even if you run breathers you will still get condensation. I had that same problem on the dragster and I was running valve cover breathers. It's just the name of the game in the colder months.
Basically, just keep an eye on your oil either on your dipstick or when you do an oil change. You should be fine though.
Glad to hear that you found your electrical problem too.
Basically, just keep an eye on your oil either on your dipstick or when you do an oil change. You should be fine though.
Glad to hear that you found your electrical problem too.
Teching In
Joined: Nov 2008
Posts: 38
Likes: 0
From: jacksonville AR
its no big deal all motors will do that it is just condensation its only on you cap not like its getting a milkshake in the crankcase i have seen that on several motors over the years pcv valve has nothing to do with it just change your oil cap the o ring on it is not sealing tight enough trust me i been in the engine biz for a long time
i'll definitely keep an eye on things. yeah i have no pcv, where would i need to hook up breathers to? i believe its entirely closed off. now i have a new problem, went to start the car today and had a little snafu. heard an electrical "click" and lost all power to the car, the cars wired battery -> starter -> alternator -> engine bay fuse box. battery's still good but everything just got cut off, i'll have to crawl under and do a whole troubleshoot... irritating since i've been doing that for the past 5 months almost every minute of my free time
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finally had the time to take it for a drive today. i let it warm up and gave it a good rompin, i have an autometer temp gauge and i was around 220-230 ( dont have fans hooked up yet), pulled her in the garage and still coolant in the oil cap , it smells pretty bad too, something vile to say the least. not sure what the problem is? ive yet to check the radiator because its still hot, but maybe i have an air bubble or something? if i start to overheat and get white smoke then i'll at least to be able to diagnose that its a blown headgasket, if so then new heads for me 
eeeek, what a pain
eeeek, what a pain