mrplow1

Hi everyone, this is my first post on ls1tech and first ls motor I've had. Long story short i bought a 2001 5.3 from a Silverado for my ls swap in my 85 c20. I took off the intake manifold and there was a lot of sand and gravel/ beach sand under the intake manifold. And in cylinders 7 and 8 it was really oily, and a lot of carbon build up.

Fast froward until now, the engine ran bad so i checked for engine codes and none. Then i swapped plug wires and nothing changed, next i changed spark plugs and cyl 8 was oil fouled bad, and cyl 3 and 4 had oil on the spark plug threads? The new plugs made it run like it should.

Now I'm having problems when the truck gets to operating temp about 192. degrees and when in gear, stopped at a light it feels like its having a hard time idling. If i put it in neural it idles fine. And yes i have the tcc switch wired up through a relay off my brake switch, and I confirmed it works. Its almost like the engine is misfiring when it does it.

Ive attached a picture of what the engine looked like when first took off the intake manifold. The engine has 150,000 miles.

Am I low on compression? or valve seal leak? or is there any problems with this motor having problems on cyl 8?

Thanks I'm new at this motor and need help.

mr93ws6

im not the most experienced guy on here, but id say its possible that you have bad valve seals. try a compression test and see if those cylinders are reading low. its also possible (worst case scenario) that the piston rings could be bad allowing some oil to creep into the combustion chamber. never seen gravel/sand get under the intake though...

99z28monster

iTrader: (3)

Mother of god that looks bad. Do the compression test to see if you have serious issues. Its simple to do and worth knowing how your cylinders are.

mrplow1

I'll try and get a compression tester after work tonight and report back with the numbers. I thought it was odd that there was that much sand under in intake. Also the coils for 7 and 8 have a lot of oily residue when i got the motor, and the valve cover on that side. Could it be from blow by, blowing out the valve cover seal?

99z28monster

iTrader: (3)

what did that motor come out of? looks like it might have spent some time in a 4x4 vehicle.

mrplow1

The motor came out of a 2001 Silverado that was stock, it was in a collision and bought at auction. The place i got it from has a 30 day warranty but it took a few months to get all the parts needed to do the swap and I wanted to know what exactly is wrong with it before i attempted to contact them.

I ordered a compression tester it should be here tomorrow and if it does i will have time to do a compression test and hopefully get to the bottom of this.

Overall the swap is pretty easy, as long as you get all the right parts the fist time. I've attached a picture of the 5.3 in my 85 chevy

mrplow1

I did a compression test and all the cylinders were at 170 to 175. Most of the plugs had some oil markings on the tips. Not much but I haven't put many miles on the plugs since i changed them. I'm leaning towards my valve seals are leaking a little. Maybe a tune would make the engine run better.

robert4940

iTrader: (3)

definitely would be looking at valve seals leaking...tune might help but with plugs getting oil will not last...take care of valve seals first in my opinion.
the way engine looks dirty on outside might be indicator on what is going to look inside. heard of draining quart of oil and adding quart of trans fluid to clean engine from inside. heard works pretty good but never tried it personally.

jcag2189

I've done the drain a quart/add a quart of ATF fairly regularly in the past, just did it last week on my 06 Mustang and a high miles 2.5 Ford (heresy, I know!)

An old shop teacher of mine turned me on to that trick ad was a big fan of it. Has always done well for me as an engine cleaning oil treatment, but it's just that. Taking care of the valve seals now is where I would look into.

truckdoug

iTrader: (25)

the trans fluid thing is from bygone days of non-detergent oil. (trans fluid has a ton of detergents in it) I have done it, but I wouldn't risk it these days. Just run a good quality name brand oil. Why risk knocking some crap loose and having it stick to a bearing journal? I am against any snake oils type fixes these days.

even with low miles, these motors have a tendency to ingest oil into the intake through the PCV. In a high-mileage motor it could be a bunch of oil.

Maybe give an oil catch can a shot? google search "ls1tech catch can pcv" there are a bunch of good threads on it.