O.K. guys, I'm new at this so bear with me. I have a 98 Blazer that has a loud knocking noise. Sounds like it is coming from the front around the water pump area or maybe underneath. It is steady from start-up and idle and gets faster, but quiter during normal runnung around. My oil pressure also starts up around 50 and as it warms up to it temp. around 210, oil pressure decreases to 10. I changed oil and filter it helped a slight bit for a while. Please help.

jjds

 

i had a knocking noise in mine earlyer this year. id lose power and oil pressure. turned out i had a spun bearing and yea. but dad works for a parts store so we got it rebuilt :] so throwing that out there as a possablilty

 

sound like your oil pump is going going soon to be gone. i am presently tearing down my motor due to loud knock and sudden lose of all oil pressure
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Could be a lot of things. Have you tried searching in the engine & transmission section that has the model & year of your vehicle?