I have a 1990 GMC Sierra with a 350 that is collecting oil from somewhere and slinging it all over the engine compartment. Not to mention the squealing and noticeable wear. I pulled the cap off the power steering pump and sure enough it was low and the seal was all twisted and split. I'm thinking this is the culprit, but I'm also thinking that the cap is far enough a distance away from the belt that the fluid shouldn't reach the belt.

It could be coolant with rubber particles in it, making it black. I have a leaking thermostat gasket that I'm also going to address, but I don't understand how the coolant would work it's way forward to the belt.

Is there any other place the oil could be coming from?

 

Harmonic balancer seal. Seen that before, friend was losing 2 quarts a day and there were never any puddles under the car.

 

If the smog pump is gone off of it, one of the bolt holes looks RIGHT DIRECTLY INTO the crankcase. Might even be able to see the crank in some blocks.



Put a short bolt in that hole w a drop of sealer on the threads.

 

The truck doesn't have a smog pump, but a guy from Oreiley's seemed to think that it didn't have one from the factory. I'll take a look at it tomorrow in the daylight.

I noticed some dried coolant at all of the rad hose connections. Got new hose and clamps and a new thermostat gasket. Going to get the coolant leaks under control and see if I still have a problem wit fluid on the belt.

 

Doesn't matter whether it "came with one" or not; that hole's been in the small block since 1955.

Make sure it has a bolt in it.

Might want to take it to the quarter car wash, along with a coupla cans of engine degreaser, and clean it up; not only makes it eeeeezier to SEE leaks, but makes working around them A WHOLE LOT less unpleasant.

 

I agree on the harmonic balancer seal spraying oil all over the place. You would notice it after heavy braking as the oil shifts forward and comes out while running.

On mine the balancer was still good so I picked up what's called a harmonic balancer sleeve and tapped it on and replaced the seal. It worked really well.

 

I looked around the block last friday for that open bolt hole and sure enough, there is no bolt in it. I don't see any oil around the hole, but I do see oil built up on the front lip of the oil pan. I will put a bolt in the hole tomorrow and see if any more oil builds up at the front lip of the oil pan.

If that doesn't fix the problem, I'm almost positive it's the front crankshaft seal.

 

Quarter car wash it after you put the bolt in. Maybe even, BEFORE, and put the bolt in before you leave the car wash.

In fact, back about 35 or 40 years ago, when I learned about that bolt THE HARD WAY (back before Algore invented the Interwebz), that's EXACTLY what I did... put the bolt in at the car wash. I was amazed.

 

Well I started working on the truck today. I put the bolt in the open hole and started to address some coolant leaks that could possibly be getting on the belt and drawing oil out of the rubber and making it seem like oil being slung all over the engine bay. The substance does not smell sweet as much as I can tell, but I want to rule it out completely. While removing the bolts to the thermostat housing one them decides to break. Now I've got that to deal with.

I'm guessing since most of the oil is on the driver side, the power steering pulley has a wobble to it, and I'm losing power steering fluid pretty fast. The oil is most likely coming from the power steering pump. I have replaced the cap to rule that out, but I'm willing to bet I'm going to have to replace that pump. Won't know till I drive it, and that might be a while now that I have to deal with this broken bolt. I'll update tomorrow.

 

Got the coolant leaks squared away. That's definitely not it. I put a bolt in the hole described above. Not it. The power steering pump continued to lose fluid fast. That pulley had the most oil build up on the back compared to the others, the crank pulley a close second.

The truck is now sitting in my driveway ready to get a new timing cover gasket, front crank seal, oil pan gasket, hamonic balancer, power steering pump, high pressure and return lines, idler pulley and tensioner to be installed by the end of this weekend. If the squeal isn't resolved then, I'll be puzzled. When I pulled the timing cover this morning, I noticed the chain was pretty slack. I figured for less than $20, why not replace it with a double roller?

I'll update late with the outcome.

 

Will probably need to do some work on the block to fit a double roller. I've always had to trim the edges off the three main oil gallery bosses at the front of the block, behind the cam sprocket to make room for the wider chain and sprocket. I wouldn't do it myself unless I had the motor torn down so I could also tap the galleries for threaded plugs.

I have seen the same oil on the belt problem a few times. Start the engine and have a helper hold the steering wheel at full lock while you look at the PS pressure line. See if it isn't spraying fluid at the belt.

 

Thanks for the warning. I'll measure the thickness of the chain compared to the original, but it didn't seem that much wider to me.

I have new lines to go along with my new pump, so there shouldn't be an issue with that.

 

Why would I need to tap the galleries for threaded plugs?

 

I got all the work done that I said I was going to do including grinding down the oil gallery boss to allow room for my double roller timing set. There was only one that might have interfered. Also cleaned the pulleys I didn't replace. I'm squeal and leak free at the moment. I will keep an eye on the seals to be sure.

 

Threaded plugs naturally hold under higher pressure. They are vital when we install a high volume/high pressure oil pump running 80psi. The rear gallery plugs are threaded from the factory because they are external to the block. The factory cheesed out on the internal plugs and just used drive in soft plugs instead. Also, when you trim down the bosses at the front of the block, you generally take off some material one one side of the gallery, which may encourage a soft plug to blow out. Alot of people get away with running the factory soft plugs. Don't worry too much about it. I'm just throwing the info out there as food for thought.

Like I said, I only do this if I have the motor torn down. Otherwise metal fragments may be introduced into the oiling system and will damage engine internals.