72' GMC Tiny engine fire. Help!

[ItzhakRoberto]

Good Afternoon Fellas,

I'm fairly new to these trucks...i had a 71 i was going to fix up but plans did not go accordingly. I now finally got ahold of another one, a 72' GMC ....i have a couple of pics i will post.

I have been on this site for a year or so and have somewhat learned how to use the search bar which gave me some ideas where to start to look for why the smell of gas is so strong in the cab LOL

I know have another question...

I'm not quite sure but on the passenger side of the engine, near the middle of the exhaust manifold near the head, or maybe its the valve cover? there was a little seepage of engine oil..

My alternator belt broke while driving it which caused it to slightly over hear ( i stopped it as soon as i could, did not drive it far like that). and i saw there was a little oil there around the top.

ACTUALLY there was a small flame like the oil or something caught fire.
Instantly put it out but now i'm wondering as to what could have caused it, what should i look for?

I've seen it seep a tiny bit near there once before, but then again kinda just bought it. Not sure what the issue may be.

Any push in the right direction would help.

Last question, on the intake there is a wire or sensor with the wire cut in one of the pics, can someone help identify?

Don't laugh at the coolant reservoir, it was to simply make it home!

Thanks guys

[AussieinNC]

That cut off wire in the manifold front water port is an aftermarket temperature gauge sender wire...perhaps a previous owner installed an aftermarket gauge set then removed it...

The oil smoke, slight fire is a build up of old oil that ignited due to the overheat situation...replace the rocker cover gaskets...try and find some one piece rubber ones...stay away from cork...also, make sure the bolt areas in the rocker covers is not dimpled down...and put some red loctite on those studs holding down the rocker covers...those studs have a bad habit of coming loose....

Clean out that oil build up with carb or brake cleaner...

WARNING...COLD ENGINE ONLY !!!!!

Gas fumes inside the cab...yuk!!!

Usually a rusted tank, or bad fuel rubber lines, or a cracked filler tube to tank connection...either way,,,safest way is to move tank to under the bed...search "Under Bed Fuel Tank" on this forum...there are lots of posts...

That's a nice GMC you have there...

BTW...I always carry a spare fan belt...always...

[LockDoc]

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A leaking exhaust manifold could ignite the oil also. Have you tried just tightening the valve cover bolts down a little bit? Don't get carried away and twist them off though.....

LockDoc

[snipescastle2]

That soot buildup looks like the manifold has been leaking as well, have you noticed any considerable exhaust noise under the hood? If the leak is bad enough, flames will shoot out of the gap where the gasket was blown out.
hth,
Ben

[Steeveedee]

Your fuel smell could be the gas cap. Pop it off and see if the gasket is cracked. I ended up going with a non-locking cap because the locking caps go bad about every two years.