My 2000 blazer that I just bought has a annoying oil leak, I can't seem to find where it's coming from if it's the rear seal or the pan gasket or a manifold leak.... I have yet to get the rubber plugs out of the trans yet to check for oil on the plate.... If there is oil is that a sure sign of a rear main seal? if so is it worth repairing or just waiting til it completely lets go and putting in a rebuilt motor?


2000 blazer 4x4 4-door with 152k miles

 

Oil on the flexplate is a sign of a rear main leak. Replacing the rear main requires either pulling the engine or pulling the transmission... Lots of work and can be quite expensive if you are having a shop do it.

 

Any idea on the cost of rebuilding the engine if I have to pull it?

 

Junkyard motor there is plenty of them, if you plan on keeping the truck for a long time you can rebuild the 4.3 at your own pace

 

There aren't may junkyards around with newer motors like these, so i'll have to have one shipped here... not sure how long the rest of the truck will last, does need new brake lines and possibly fuel lines also...

I only paid $1000 for the thing... so far all i've done is replaced the 4 ball joints.... it does have a rebuilt transmission with less then 50k on it...


on a side note... does the front axle only lock when the engine pulls a vacuum? or should it be locked even when engine is off? (4x4 engaged of course)

 

I had a bad oil pressure sender. It was spewing oil and it would drip down the back of the engine right on to the exhaust below. Wind from driving blew the oil back and it looked like it could of been coming from the transmission pan, or oil pan.

Anyways. The oil pressure sender is by the distributor. Look in that area and see if you see a puddle of oil in the area. There is lovely little ledge back there where the oil can puddle up. If the oil is black it's easier to see. If the oil is pretty fresh you have to look carefully, because it blends in with the manifold, maybe even feel back there with your finger or with a white paper towel to confirm it's dry. If you see oil there, I would suspect this is your issue. Mine was accompanied by abnormal oil pressure readings on the instrument panel. It also would not leak unless you drove it for awhile, which helped confirm my diagnosis of oil pressure sender.


It's not incredibly difficult to replace, but you have to remove the distributor to replace it. At least I don't know how you can do it without removing the distributor. Of course if you aren't familiar with removing the distributor and reinstalling it you will want to study up on this otherwise you risk throwing your car out of time. You have to reinstall it exactly how it came out.