So I have a 1990 GMC Jimmy s15 4.3l 4x4 with 186k miles and I’m having an issue where smoke appears to be coming from the back of the engine after I start driving for 10 minutes. I semi recently bought this vehicle and there were wires unconnected and vacuum hoses loose, and I fixed all of that except for one Orange/white wire. I originally thought it was the thermostat cause the temp gauge was hitting the red but then it would instantly drop down, so I got a new thermostat, and put it in and noticed there was a grounding wire loose, so I grounded it and now temperature is normal. I flushed the coolant and put new fluid in. I changed the oil filter and changed the oil plus just recently added sea foam to the engine yesterday, I do have a pretty bad leak coming from the oil filter lines down to the engine, and I’m starting to think it just maybe the issue. So I clear most of the oil off the engine and it still happens but then again obviously it’s still leaking oil decently bad. Is there a way that I can bypass the modified longer lines where the previous owner must’ve been sick of going under the car to change the filter so he got the filter put near driver side headlight, and just put the filter back on the engine block, like how it originally came? Or maybe anyone who has had the same experience or just thinks it could be something else. Thanks again!


Edit:
here’s some photos if this helps at all, the first two photos you can see this are the oil lines leaking that allows oil to drip all the way down the lines. So I can’t tell if it’s the same one leak doing it all or multiple including the seal where it connects to engine. And also looks as if I’m leaking oil down onto the #6 spark plug which I assume would be coming from the oil fill pipe coming out of the right side valve cover.

 

Back of the engine? check that rear main seal, on your 1990 you probably have a 700R4 so pull off the inspection cover and see if its got oil all inside around the flexplate and converter, if its a Manual tranny im not sure how those are configured but there should be an inspection cover or blockoff plate of some sort around the bell housing. Do get those cooler lines fixed ASAP, it will kill the motor.

 

thanks so much for the reply! Yeah I was definitely going to fix those oil cooler lines. Is there anyway I can just get rid of them and put the filter back onto the engine like it was originally made? I’ll be getting under the car tonight and tomorrow so I can assess the tranny/CC/front differential plus where the cooler lines connect to the oil pan. I’ll take photos because I know there was a ton of oil residue from previous owner left all over the front differential and CC.

 

The cooler lines are how it was originally made, actually, your truck being 4WD a block mounted filter is not an option unless you do a suspension lift that involves dropping the IFS differential down. replace the cooler lines with a GM set, and make sure you use new gaskets for everything when you reassemble the adapter.

 

The bolt from the adapter to the block can possibly be reached by using a very long extension on a ratchet.
Check for the correct seal rings. They are hydraulic ones made from an outer aluminium ring with a rubber insert. (Should come with the oil lines, but make sure they are added).
There are two sets of hoses.
1 long one from the back of the block along the oil pan, then up behind the steering pump and a flex hose part, then again aluminium tubes to the filter adapter.
1 shorter one from the oil filter adapter to the heat exchanger on the left side of the radiator.

Usually both need replacing. I'm pretty sure you have an oily mess also below the left headlight where the vacuum accumulator is, left of the radiator.
After burning through two sets of remote oil filter hoses I had my hydraulic shop fix them for good. We used threaded connections for the flex part which makes them 4 or 5 parts that can be easily assembled. But it involves some tinkering and a willing shop with the correct hoses to make such a fix.

https://blazerforum.com/forum/builds...-cooler-29968/

 

mine only has 2 hoses running the same path from the oil pan as metal tubes, to then rubber tubes (but seems to be metal underneath) all the way until oil filter and that’s all I have coming from the filter at least. But I think your saying there’s another set on the left side that goes from radiator to engine block as well right? On the left side I have a lot of oil leaking but it’s way in the back right past where starter is.

 

There is only two lines from the back of the block to the oil filter location. Feed and return. "IF" your Blazer is equipped with the heat exchanger in the radiator you will have two more lines leaving the oil filter adapter on the left fender towards the radiator.

There is in any case only two lines as you describe them from the block to the remote oil filter adapter.