Help! Serious issues or just condensation?

[Wile.E.Coyote]

How can I tell if I have a head gasket issue or just condensation in the crankcase?

Facts:
White foam under oil cap
White streaks in oil on dipstick this morning after sitting over night, long trip last night
It's been exceptionally cold here in Chicago last few weeks, highs in the single digits, wind chill -25F
Radiator was changed 2000 miles ago
I changed oil 1000 miles ago and did not notice coolant in the oil
It does seem to take a while for heater to warm up and running "cool" even when I've been driving a while. Temp gauge sometimes stays 1/4 way between C and F.
95,000 miles on the 4.0L V6, otherwise running great

Is there some way to check if it's just condensation? Does the 1GR-FE use a thermostat? Is there some way to change it to run hotter?

Thanks!

 

[JEL]

99% of the time white foam under the oil cap is condensation. Sounds to me like you have a thermostat that's sticking open, and given your extreme cold over there lately, you're not warming up. Typically that head gasket will cause extremely rough running on start up, throw p0636? code, and trip all the warning lights on the dash. Your temp gauge should run half way between, so I suspect you're having a thermostat issue, it's probably never been changed so I'd say it's due, add to that the extreme cold and it probably packed it in.

Do you have any oil in the coolant reservoir?

 

[BlackWorksInc]

The 4.0Ls get some Lung Butter going on in colder weather. Sounds like the engine may not be getting hot enough to boil off the condensation.

 

[Wile.E.Coyote]

No oil in the coolant reservoir. I checked oil again after letting it warm up and didn't see any more milkiness. Im going to continue to monitor and probably swap the thermostat when I get a chance. How difficult is that job?

I saw that there is a TRD coolant cap that is supposed to release at higher pressure and this increase the boiling point of the coolant. I wonder if that would help?

 

[Wile.E.Coyote]

I know this is year old, but thought I'd update in case it helps someone else. The issue is just condensation. Over the summer the white foam in the oil cap went away and returned when things got colder again, so it seems that I'm just not driving long enough to burn off the condensation. Still might change the thermostat, because it seems to take exceptionally long to warm up in mid-winter, but it's tough to judge because when it's 0deg here, I'm not sure what 'normal' warm up should take.

 

[repo]

The 4.0Ls get some Lung Butter going on in colder weather. Sounds like the engine may not be getting hot enough to boil off the condensation.

Hey would this be something to put you off buying a low miles ones vs a cheaper same age high miles one? Like 60k daily school run 4runner vs 140k long highway commute 4runner (with good oil change records)?

 

[repo]

No oil in the coolant reservoir. I checked oil again after letting it warm up and didn't see any more milkiness. Im going to continue to monitor and probably swap the thermostat when I get a chance. How difficult is that job?

I saw that there is a TRD coolant cap that is supposed to release at higher pressure and this increase the boiling point of the coolant. I wonder if that would help?

Wouldn't you want to lower the boiling point in this case? Also a new PCV valve might be some insurance.

 

[Wile.E.Coyote]

Yea, I talked to some guys at the dealership who run Supras. You're correct the higher pressure cap only helps cool at the high end, it wouldn't affect warm up time or make it run warmer. So I was backwards : /

 

[Tony_SS]

Being new the 4.0's, this freaked me out at first too. But it appears to be common side issue in the winter. Now on to the fun stuff. Lift, wheels and tires!

 

[repo]

Yea, I talked to some guys at the dealership who run Supras. You're correct the higher pressure cap only helps cool at the high end, it wouldn't affect warm up time or make it run warmer. So I was backwards : /

I use mine for mostly short trips, half of the time in cold weather, so I make an effort to take it on the highway once a week for an "Italian tuneup".