Oil pressure gauge low and engine knocking?

[theratch]

I have a 91 gmc sierra 4 wheel drive, 8 cylinder club cab truck. I recently had the head gaskets changed. After the truck was returned the oil pressure gauge reads low after the truck warms up. The engine starts knocking as well. The oil stick reads full though it apears to be leaking under the truck. It also wants to and does die occasionally when the oil pressure gauge goes in the red. What do you think is causing this? Thank you.
Rich freeman

[2000CAYukon]

Originally Posted by theratch

I have a 91 gmc sierra 4 wheel drive, 8 cylinder club cab truck. I recently had the head gaskets changed. After the truck was returned the oil pressure gauge reads low after the truck warms up. The engine starts knocking as well. The oil stick reads full though it apears to be leaking under the truck. It also wants to and does die occasionally when the oil pressure gauge goes in the red. What do you think is causing this? Thank you.
Rich freeman

There is a switch that will cut off fuel if the oil pressure is too low.

From the sound of it, you have a bad bearing. The oil pressure should be verified with a mechanical gauge.

//2000CAYukon

[fuzzypuppy]

I'm wondering why the head gaskets needed to be changed in the first place?
If the oil pressure was good before it went into the shop I would suspect the shop used the wrong head gaskets as replacments and are at fault therefore responsable for damages. when the motor comes apart for repairs this can be verified.
Unfortunatly if the engine was run even only a short time with very low oil pressure and if there is a knock the damage has been done.
About the oil leaking, it could be that the "mechanic" uh "person" who installed the wrong head gaskets did a poor job of installing your intake manifold and the leak is coming from there at either the front or rear of the manifold.
I just noticed that your post is a couple of weeks old so I'm not sure if my reply would be of any help but I would surely have a different shop for any further repairs and documentation of the previous shops faulty workmanship so you can recoup the cost of these repairs.
I do hope you have better luck with shops in the future.