Help
my 96 is constantly pushing coolant out the overflow and temp guage pushes past 190+ and heater blows cold air. i was thinking of replacing thermostat and short hose at themostat housing to engine. previous owner rigged a air compressor petcock to relieve pressure?? and a coolant jug at the overflow hose to catch coolant and put back in after it pushes it out either by overheating or ??? usually happens when slowing for lights or slow driving in town highway usually no problems unless traffic backs up like today and heted up to 230 before I could get off the road

 

Head gasket? Sounds like a pretty clear case, unless the head is actually cracked.

 

now today I was easy on the go pedal and it didnt overheat or push it out at all drove in total about 70 miles hwy, town, and in snow in 4x4 and out of 4x4 had defrost/floor heat on and blew warm, guage never went past 180* acted fine.. what the h...??

 

Sounds more like air in the heater core. If the system runs low on coolant it will draw it from the heater core when there's nothing in the overflow bottle. Take the cap off the radiator, start the truck and warm it up. Turn the defrosters on high fan, hot temp. When the engine is fully warmed up, rev up the engine, hold it for a bit then let idle. Repeat as necessary, adding coolant as needed until you get hot air out of the defroster. Top off, put the cap back on and add coolant to the overflow bottle to bring it to the HOT line. I was a mechanic at Detroit Radiator many many many years ago.

 

I agree...this is usually the case with your symptoms

 

had the same problems on my 97. is there oil in the coolant? my problem was the oil cooler take it out ant have it tested before you pull the head.

 

i have diagnosed this problem many times as the fan clutch.......i could be wrong but ........if you can spin the fan easily with the engine off, replace it

 

ok I will try these .. I suspected its not the head gasket, because it doesn't overheat unless all the coolant gets pushed out.. i had a thought of the oil cooler thing... but whats wierd is the coolant coming out into the jug I have catching from the overflow hose off the overflow resevior is green but the coolant in the actual overflow resevior is brown, I also noticed the radiator has oily residue on it so im going to check oil cooler first, oil has been low havent noticed any coolant in it. thank you for the help and replies, please keep them coming

 

Next time you drive your pickup and its good and warmed up get on it real hard a few times if its a head gasket it will push coolant out the overflow.

 

Yeah, oil in the coolant is a whole nother thing. Oil cooler, possible, what's your trans fluid look like (provided you have an automatic)? Brown is probably engine oil but I've seen brown trans fluid - not what I'd want to see tho!

 

yeah i would try the oil cooler. talk to schied today and it is very rare but checking it first would have saved me bunches. your truck sounds just like mine was doin lucky for me i found a cooler from a guy on ebay for $35.. it is $315 from cummins.

 

+1 head gasket. Take the belt off and run it with the upper water plug out. If you get bubbles, you got a compression leak into the water.

 

ok because of lack of money I have been checking what I can, but w/o $ I cant buy parts
but heres some updates.. my coolant is frothy looking especially in the overflow resevior and after I heat up and it blows cold air thru the heater. and my truck is a stick NOT AUTO. I really am thinking when I get enough $ together Im going to first buy, water pump, thermostat, clutch fan and possibly radiator ( my radiator is greasy and has some corrosion Im guessing the oil cooler is internal to the radiator??) oil looks good It fairly clean and isnt frothy or white looks good from what I can tell.

my thinking is that these components are old and have presumably 243k miles on them so I need to replace anyways last owner put alot of front end parts. maybe Ill just sell it and get a different cummins im not to fond of 4:11 gears anyways like the torque but I dont pull much and I drive hwy alot so 70 is like 2500 rpm although it takes off like a rocket even fully loaded...

 

hi
maby rad is cloged on outside with old oil / dirt .

remove rad and carefully wash out the fins , usualy lower half gets cloged .

also flush rad with some clean water , and flush heater core with garden hose, both ways .
install a new cummins thermostat .
dont think fan clutch would matter in cool weather ?
also new rad cap , low psi = overheating .
add a small bottle of stop leak , i use the silver barsleak .

 

well I put over 250 miles on it yest and before I started driving I topped off the radiator with it running and def on full and motor warm... well I noticed if i kept it around 2000rpms or more, even in town, the temp guage would stay good and for the most part heater would blow WARM never really hot. hwy constant speeds and rpms 2000-2500 rpms, it would even run cold by the temp guage like around 140* or the first mark. temp guage would climb to 190+ if im idling at a light and if I would stay in low gear and keep the rpms around 2000+ the temp guage falls rapidly and doesnt overheat. I also noticed the serpentine belt is pretty bad, maybe at idle it slips? It doesn't squeal but it is oily from coolant spills all over motor bay... Thank you everyone for your input and advice