GM 4.3L, No oil change in 2+ years

[oggb]

Background info:

• 1995 Chevy S-10, 4.3L V6, 52,000 miles
• Transmission has no 3rd or 4th gear (auto trans.)
• Oil was last changed roughly 2.5 years ago, truck might have seen 1000 miles before the transmission went out
• Max trips of 0.3 miles
• Coolant temp rarely reaches operating temp - perhaps twice a month, and never for longer than five minutes.
• Oil has probably not seen operating temp in 2 years
• Oil was 5w-30 "Federated Auto Parts" brand

This is one of our work trucks. I am not in charge of maintaining vehicles where I work. I was working alone on a saturday, got bored, and decided to change the oil in this work truck.

As I unscrewed the oil filler cap a ton of what looked like rust fell out of the recessed portion of the cap. The dipstick read over full when I checked the oil prior to draining it. The oil ran out like water, and was probably more gas than oil.

I pulled the valve cover and it looked like someone had poured asphalt in the engine. The PCV on the passenger side valve cover was sludged up and hardly working. It looked awful.

The truck does not smoke, was not known to consume oil, has only a very small oil leak from (I think) the passenger side valve cover gasket, has one very slightly noisy HLA, is still running on the original plugs and wires, and starts/runs as well as it ever has.

I filled it with 3.5 quarts Pennzoil 5w-30 and one quart Napa Fleet Premium (the older CI-4 type) 15w-40. Thought the extra detergency might gently clean some sludge up. I almost want to use this as a project to see if I can clean it up using just HDEO.

I thought of paying out of my own pocket to put some Pennzoil Ultra in it to see just how well it'd clean things up in one oil change.

 

[5sfe91]

tough engine for sure, do you have any pictures of the valve cover off?

 

[AuthorEditor]

Yuck! You sure there isn't a coolant leak?

 

[oggb]

My hands were so covered in crud after removing the thing I didn't want to touch my iPhone with them, for fear of it too becoming sludge infested.

It looked like...

that. Pretty much exactly the same, actually. That's a different type of engine but virtually same amount of sludge.

Definitely amazed with this engine's durability to this point. I had a '99 S10 with the 4.3 and it was developing rod knock @ 85k miles.

 

[oggb]

Originally Posted By: AuthorEditor
Yuck! You sure there isn't a coolant leak?


Yeah, no milkshake look in the oil, coolant reservoir and radiator were full. I'm thinking it's just the fact that the oil never gets hot enough to boil the condensation and fuel off.

 

[Silber Igel]

Junk it! *(;-D

 

[panthermike]

I wouldn't want to pay out of pocket for this, but a cool experiment! If you do this, take pics please

 

[addyguy]

I'm suprised your work has kept this truck. 15 years old, tranny blown....I'd expect them to have junked it the minute it happened.

What are the plans for this truck?

A member on here, 'Kestas', has written about doing oil changes on his vehicles in the 1970's, and said he used 10W-40 every 6k miles, and that the oil used to come out 'all black and watery'. I bet his engines looked like this under the VC's, as well!

 

[oggb]

Originally Posted By: addyguy
I'm suprised your work has kept this truck. 15 years old, tranny blown....I'd expect them to have junked it the minute it happened.

What are the plans for this truck?


We have two trucks - one that is used for long trips which is almost brand new, and this truck which is used to carry tools, equipment, etc. around the plant. The trans. died because of the type of use it used to see:

Start truck up (cold start)
Drive truck ~0.1 miles, stop.
Drive truck ~0.1 miles, stop.
Drive truck ~0.1 miles, stop.
Turn truck off.

It would sometimes get 5-8 miles of use like this in a single eight hour period.

It was constantly shifting 1-2-3 and rarely saw speeds above 20 mph before the trans died.

So, basically, the plans for this truck are to use it like a glorified golf kart.

It was actually my idea to keep it so that we wouldn't kill the transmission in our newer truck. It has seen ~3000 miles in its first year and is being fed PYB 5w-30. It's a 2009 Chevy Colorado 4cyl auto.

I really am considering running either 5w-40 Rotella T6, 10w-30 Rotella T5, or 5w-30 Pennzoil Platinum through it for a single oil change seeing what kind of a difference it makes. Can anyone think of any other oils that clean REALLY well? Most HDEOs I would think have high amounts of cleaning agents.

 

[Nick R]

I think if you run any heavy duty cleanin goil through it it will plug up the oil pickup and oil passages. Just feed it the cheapest oil you can find till it dies.

 

[oggb]

Originally Posted By: rudolphna
I think if you run any heavy duty cleanin goil through it it will plug up the oil pickup and oil passages. Just feed it the cheapest oil you can find till it dies.


I was somewhat worried about that. That's why I didn't try to clean any of the junk out from underneath the valve cover.

 

[addyguy]

Royal Purple oils have boatloads of detergents in them - 2k ppm of Ca, and 1k ppm of Mg....that will clean this engine right out!

M1 oils, no matter what people say about them here, clean very well. I think it has a lot to do with the AN's in the basestock.

 

[oggb]

I do wonder though, how dangerous is it to even attempt to clean this engine using a high detergent oil? Like rudolphna said, if the detergents break up a bunch of gunk it might clog a passageway somewhere.

Dunno if it's a risk worth taking...

 

[addyguy]

The 'diiferential' in cleaning power between a run of the mill dino and a synthetic is not THAT great.

That is, the risk with a synthetic is no worse than when you changed the oil the other day and put PYB in - that could have done it as well.

Also, the risk of something 'breaking loose' usually comes from using a solvent-based cleaner in the oil, NOT from just using a change of oil.

I really doubt anything is going to happen - you have a 'light coating' of sludge on the engine, not some mountain of goopy mud...there are no real chunks to break off.....

 

[AuthorEditor]

Let's face it, that truck is worth next to nothing. I would just run it with the cheapest oil and filter I can find until it dies. If you want to just test out one of the HDEOs or Penn Ultra to see what it does in terms of cleaning, go right ahead, but my guess is you won't gain any significant life out of the engine. Keep in mind that if real cleaning does take place the filter is liable to clog--run shortish OCIs.

 

[antonmnster]

Looks like major condensation that just kept building and building. At least if it sat there and idled for a couple hours it might heat up a little.

 

[oggb]

I thought of doing that actually. Then I figured it'd cause massive fuel dilution, so I guess I'll try to change the oil bi-monthly or something.

And I wish my car took the massive filters those old V6s and V8s did. The filter for this engine is easily 3x the size of the filter my WRX takes.