87 gmc 1500 tbi to carb over heating

[87 grey ghost]

Hi Guys,

I got an 87 gmc v1500 that was tbi and i switched to a carberator.
For the last few weeks the truck continues to over heat and is building to much
oil pressure that it will blow the rubber oil fill cap out and push the oil dipstick out some, and spray oil everywhere.
I replaced the fanclutch and thermostat and also ran with thermo removed and still over heats the water.

Alittle more over view.
On the drivers side I have two outlets on the valve pan one is an oil fill plug and the other has a pc valve then runs into the front of the carb.

The pass side valve cover has one outlet that i ran into the air cleaner on top of the carb.

Also recently had a tranny put in if that matters?

thanks

 

[Swims350]

ok when you say you put in a new clutch for the fan did it overheat before this?

I ask because some truck swith serptine belt or all maybe have reverse flow water pumps, and so they fan and clutch are different, one in clockwise and the other is counter clockwise.

Next thing what is the timing set at?

pulled a plug to see if it's running really lean?

every tuned the carb with a vacuum gauge to make sure it's not running way lean?

 

[Mr Clean]

from N.E. Texas!

Like swim said, you could have the wrong fan, What about the water pump?, it could be a few other things, need more info. Could be a bad PCV valve, you do have it hooked up to the carb correct, bad crank case air breather.

 

[Swims350]

yea most definately, one way to check the water pump is to see if the weep hole is leaking, or with the t-stat out and it running see if it's pumping water, new ones are cheap for v-belts like $25 or so from a local parts store, and if it hasn't been done recently like in the last year, time to flush your radiator and system anyways.

 

[87 grey ghost]

Hi Guys, I talked to a mechanic last night and seems to think its a head gasket!!
I replaced the fan clutch because it wasnt totally shot but close to it and also to see if it would help with the over heating. It did over heat before i replaced it

PCV valve is good
water pump seems to be pumping ok and no leaks and i know that it can still be bad with
no leaks but I did remove the thermostat and watch it pump.

not sure about the crank case air breather? where should that be located? 350 engine 87 tbi converted to carberator

just asking A problem with the over heating would also cause the oil pressure to sky rocket?

 

[Mr Clean]

Head gasket very well could be your problem. If your head gasket is blown, you'd be leaking water into your crank case causing to much pressure in the pan.

Your crank case breather will be on the valve cover, if you don't have one, get one, the pcv valve can't do it all on it's own.

 

[87 grey ghost]

Yes it does have breather! Before i had I hooked up to the
Air cleaner but now just hanging with no
Restrictions.And still over heats.
Probably the head gasket!!

 

[Mr Clean]

Take off your radiator cap, let your truck come up to temp, so the thermostat opens. Look down in the radiator, if you have a bunch of bubbles, or radiator fluid smells sweet (assuming you have antifreeze), you have a blown head gasket. You can also pull your spark plugs, if they are wet......you have a blown head gasket.

Do yourself a favor....replace both sides, if your going to have to replace head gaskets, while you have it torn down DO BOTH SIDES. If you have a shop do it, it's going to be a little more to do both, but it is cheaper in the long run.

Had a buddy that blew a head gasket, took it to a shop it was 1400 to do both 1100 to do the one that was blown. So he paid 1100, and 3 months later he was paying another 1100.

 

[87 grey ghost]

got a guy that's gonna give me an estimate but if its that much I'm just gonna put another motor in for about
$500
When I get home today I'll smell antifreeze along with pulling out some sparkplugs. Thanks for the info

 

[Swims350]

yep could be head gasket.

as for the breather it's not doing anything on it's own, when it's in the air cleaner is can get some vacuum and help it pull out from the engine.

hook it back up as it was or if not use a filtered breather cap.

I've heard both ways, one being is sucks clean air in from the cleaner, as the pvc sucks it out of the engine into the carb the tube pulls clean air back in, but have also heard it sucks air out just like the pcv into the cleaner as the pcv does.

anyways,

as he said, check the oil for antifreeze or water, check the water for oil or exhaust type smell, I've seen one black and smell like burnt exhaust or something burnt bad before.

and again as he said, it makes NO SENSE at ALL to EVER do ONLY 1 head gasket on ANY vehicle with 2, you are down that far, and that much time and money, it won't take but maybe 15 minutes to yank the other.

Also $500 for another engine is cheap and must be a used one, buyer beware it could be in not so great of shape. Hear it run or drive it first if anyway possible.

I would do it myself but I've done plenty and being new at it can be scary.