triple-point

Here's what I see:
1990 F150 V8 302 with 175k
Under the hood near the coolant reservoir I see splatterings of coolant under the reservoir. I thought it was a crack in the reservoir, but traced it to the oil cap ventilation tube. Seems that coolant is coming up through that tube, into the air filter and then leaking out. I opened the oil cap and there is white frothy looking stuff.

The oil in the dipstick looks fine and I don't see any increase in oil level through time. Truck drives fine and has power. I'm not sure how much radiator fluid I go through since I just changed the radiator and haven't monitored levels since.

Maybe related: if I drive for while (30 minutes highway speed), then stop at a stop light, the oil pressure indicator drops (dummy gauge) and hovers low until I either put it in park, or accelerate.

It is below freezing now in my area.

Questions:
1) is it a blown head gasket?
2) how long can I drive it without having a major breakdown on the highway?

mitchalvin

If the milky junk is only contained to the oil filler cap than the most likely cause is condensation. Check you pvc valve and make sure that the filter on the end of the breather cap is in good condition. Do you loose coolant if you do how quickly does it leak out? Do you end up with the truck bubbling into the coolant tank?

abycat

Make sure you warm it up. or at least let it reach operating temps before stutting it down. I bet you do short trips.

triple-point

To answer some of those questions:
1) yes, mostly short trips < 3 miles. I do let the truck warm up before I drive it. I sit in the car and let the truck run through its cycle before it settles down to a lower rpm. Takes maybe 2 minutes.

2) The PCV valve is new and I changed the old breather filter because the old one was nasty. I'll look again, but I'm on travel right now (truck is sitting at airport). The thermostat is new too.

3) There is no bubbling in the coolant reservoir. I've watched very closely and at various times.

4) the coolant temperature gauge never goes to the middle...it stays on the low end of normal. I've only had the truck for two months, so I don't know what 'normal' is.


Why does condensation happen? Is it a problem, what does it mean? and should I worry about it?

Again, the oil in the dipstick is fine. I'm not looking for extra work (i.e., changing intake or head gasskets), but don't want to blow an engine on a rookie move

91trilla

i drive a 91 with a 5.o and my normal operation temp is just over the n

abycat

Might need a new thermostat. id start there. if it cant run at normal temps it cant burn off moisture. clean off all that junk and throw in a stock temp thermostat and dont worry about damage, it is not a big deal. if corrected i should say. you could even run a oil system flush additive before you change your oil next time. just read directions and follow them.

triple-point

Thanks folks,

Looks like condensation. I took a chance and drove it over 200 miles on the highway past couple of days and not much condensation anymore. The Coolant reservoir is full (so is the radiator),so I'm not loosing much/any coolant. The spray that came out of the oil cap breather tube was a very oily watery mix, so it may not be much coolant after all. I'm gonna keep watching levels, dry out all the condensation from the air filter area and hope for the best. Maybe change the oil sooner than later just be be safe.

Thanks for the help

white89gt

......

Stupid "RELATED THREAD" stuff really sucks.... post was not intended for this thread.

Steve83

I agree - it's VERY annoying. I wish there was a setting to turn that crap off.