FivePointOhh

this is for an inline 6 jeep grand cherokee. mid 90's i think. its a guy at work. his car overheats so i asked him the usual questions. he said its mostly overheating at a stop so i thought fan or something but he says its when he drives its still hotter than normal. but also he said when he got out it smokes from under the valve covers. is that a bad PCV? what else can i look for. should i start with a rad flush and thermostat replacement?

what else can i look for or questions i can ask him. he said theres no leaks or anything and no loss of power really except when its really hot. but when hes driving and it cools slights the power comes back. he is losing coolant. not leaking. we're hoping not a head gasket but i told him its possible. but the smoke from the valve cover is whats puzzling me. could that still mean head gasket?

mjr46

depends on how much smoke your talking about and if it's just after you shut it off and remove the oil cap.........as for the overheat you can get a block check kit and lower the rad colant level and check for hydrocarbons in the cooling system that'll confirm a head gasket issue... I wouldn't just slap parts on it...confirm your diagnosisand I'd ask the customer when the problem first started and if he let it get sky rocket hot then the root problem could of been a t-stat but now he has a secondary problem??? possible head gasket so if the block test confirms a head gasket I'd sell him a t-stat and check the flow of the coolant in the radiator when it's apart by caping off one end of radiaitor and fill it with water and then remove your hand which is what I use and see how quickly it drains also inspect radiator fins for calcium build up inside the radiator if you can see them with a light

Curlytop

thats' where i would start rad,tstat, and fan. the valve cover smoking is puzzling. is he sure it coming from the valve covers and not somewhere else. i'm not sure would have to see it. sorry! too many variables out there.

88_LX

the smoking could be from the valve cover gasket being old and oil is leaking and dripping onto the exhaust manifold, for over heating it sounds like the thermostat is stuck and the fan wont turn on, but i would also get it pressure checked, flushed and filled along with changing the t-stat, check the wiring for the fans to make sure it isnt electrical

WhiteFoxGT

Needs a water pump....

FivePointOhh

ok i did some preliminary inspection during my lunch hour. check the rad and it was empty but overflow was full. so i filled the rad started the car. coolant cycled through but i dont think its pressurizing all the way, the coolant isnt filling the top hose completely....i can still squeeze it when the t state opens up. there is calcium build up around the top of rad inside.

i do hear a slight tick from the rocker area(compared to the mustang its more evident...louder. not sure if thats normal i havent heard the car before.)

i checked the oil and it doesnt look milky but its hard to say with such a small sample but it drips, extremely viscous and runny....but it still looks good.

now for the valve cover. once it got hot, i didnt see anything at first but when i checked the oil a little poof of smoke came from under the "fill oil cap" then from the firewall side and driverside part of the valve cover there was a steam looking vapor coming out. at first it was a slight seep then it was more constant like when you boil water and the steam steadily comes off the top....like that.

so i turned off the car opened the oil cap all the "steam" escaped looked inside and i couldnt tell what was wrong.... but most deff. coming from the valve cover. also the fan checks out, goes on and off like it should. while i was messing with it the car got hotter than normal but not in the red. so i assume 210*-230*

thats all i could get done before i went and ate then now im back to work. anyone able to narrow it down better with that? btw, no dripping of anything...from anything, block is dry from all sides that i can see and nothing falling on the ground. i also asked him how it started he said when he was sitting at a light coming to work he all of a sudden noticed the temp was in the red so he turned the heat on full blast, got out check under the hood, saw the smoke so he hopped in the car and drove 2 more blocks to work and shut it off, he said it got slightly cooler on the drive but not all the way back to normal.

mjr46

did you perform a block check??? ya' know the little bottle with blue /greenish fluid that uses a siringe/bulb that when exhaust gases are getting into the coolant it'll turn the fluid in the test vile yellow = head gasket issue or cracked head

FivePointOhh

yea i know what test you mean but i work at an insurance company full time and then car on the side. dont really carry a block check test kit in my utility belt although i have considered it

ill perform that test tomorrow and see how she comes out. then ill know where to go from there.

mjr46

ohhhhhhhh I see..I thought you were working on a customers car at a shop.....my bad!!!!

FivePointOhh

fixed that for ya

haha its kool man. im known as the mechanic here, they should open me a shop downstairs in the garage! lol. i always end up making something or fixing something. lots of people at my work or my friends who dont have a clue which make me feel better because i dont know everything there is to know....but im not afraid to work on stuff....some people scare me how neglecting they are to their car, i cant believe they actually bare children into this world and they survive.