1986 Chevy Astro Van CL 4.3

[OldBlue727]

Hello all!!! new to the AF, and glad to be here. I have a 1986 Astro van that has a lifter noise when at operating temp only at idle. goes away and runs fine off idle. have be told its probably SLUDGE...suggestions? 4.3l

[Blue Bowtie]

Welcome Aboard!

Connect a mechanical gauge to the port at the rear ledge, front ledge above the timing cover, or plug above the oil filter base (whichever is most convenient on an Astro) and monitor oil actual pressure from start until the engine is fully warmed. Anything below 10-12 PSI could be a reason for concern.

If pressure is at least 15 PSI warm it may be a case of sludge accumulation affecting oil delivery to the lifter banks, varnished lifters not holding oil, or other possibilities. My guess is that the hot pressure will be low, which is not necessarily a sludge issue.

[OldBlue727]

Originally Posted by Blue Bowtie

Welcome Aboard!

Connect a mechanical gauge to the port at the rear ledge, front ledge above the timing cover, or plug above the oil filter base (whichever is most convenient on an Astro) and monitor oil actual pressure from start until the engine is fully warmed. Anything below 10-12 PSI could be a reason for concern.

If pressure is at least 15 PSI warm it may be a case of sludge accumulation affecting oil delivery to the lifter banks, varnished lifters not holding oil, or other possibilities. My guess is that the hot pressure will be low, which is not necessarily a sludge issue.

Thanks for the info will check oil pressure and let you know what I find...

[OldBlue727]

Originally Posted by OldBlue727

Thanks for the info will check oil pressure and let you know what I find...

btw have been researching new oil pumps and I can get this one from local parts store.
Melling High Volume Oil Pump
Part No. M-55HV

ebay is selling this.

Melling Select 10550 Chevy Oil Pump Performance...race car app. I assume...

if it boils down to an oil pump problem/pressure relief valve I'm sure the local parts store will be fine...

thanks again for your help

[rhandwor]

Originally Posted by OldBlue727

btw have been researching new oil pumps and I can get this one from local parts store.
Melling High Volume Oil Pump
Part No. M-55HV

ebay is selling this.

Melling Select 10550 Chevy Oil Pump Performance...race car app. I assume...

if it boils down to an oil pump problem/pressure relief valve I'm sure the local parts store will be fine...

thanks again for your help

In older vehicles the main reason for low oil pressure is either a plugged strainer or worn bearings.

[OldBlue727]

Originally Posted by rhandwor

In older vehicles the main reason for low oil pressure is either a plugged strainer or worn bearings.

gonna drop the pan and inspect/replace strainer clean pan etc etc...