Might be he's missing something. Ever clean the throttle body? Does he actually replace the coils? how about the cats? they could be getting clogged up after all them miles..

 

yea he had the coils changed at 100k and 200k and replaced the throttle body about 6 months ago. Never thought it could be the cats though. I will let him know to have my brother check them out for him.

 

ATF is what the words say! Automatic Trans fluid! It is not engine oil, nor was it designed to be a engine cleaner!........

 

wow when did anyone say it was engine oil ??? and people use it all the time in big tractors so i was just asking if it would hurt my dads truck....

 

Pull codes on your dads truck. Even if the CEL is out.

 

Auto-RX is the only stuff I would ever put in my engine if I feel the need to clean the internals.

http://www.auto-rx.com/

It's completely safe as it does the cleaning slowly over time.

 

Transmission fluids today are basically a GP III 20 viscosity synthetic fluid for the most part with lots of ZDDP which also acts as a cleaner/detergent in your motor oil. So putting it in yer engine won't hurt it but it isn't going to help any more than using a regular motor oil. Years ago when the norm was a straight 30 oil or a 15w-40, the thinner 20 viscosity fluid would get into places that the heavier oils wouldn't and help clean and lube. Those days are gone with the newer thinner oils we see. If you want to clean the engine, use Auto-Rx but it isn't a cheap date. It's a lanolin ester like some of the esters used in PAO based motor oils. It's a slow cleaner but it does work and it requires a rinse cycle too. Avoid any quick type flushes as all they do is strip lubrication. Most of the OTC oil additives have next to nothing in the formulation and are more designed to make yer wallet lighter- nothing more.

 

Great write up Labnerd. I wish I could put the words together that clear.

 

no codes and thanks i didn't think it would hurt bu i told him to use the Auto-RX stuff if he really wanted to do something...thanks

 

Exactly! If it's worked that long, why risk causing it to start using oil? You can scour the cylinder walls and the rings will no longer seat.

 

well i am with u Bluejay but everyone knows how dads are if they wanna do something they will. i think he wants a new truck anyways cause he sold his company so know he will not have to kill a truck with miles.

 

With that many miles, if they have never been replaced, a new set of front O2's would probably help.

 

Dads will do what they want to do. I've been talking my Dad into better brake pads, and he just put another set of OEM on his truck this spring. With that many miles he will notice the improvement. There is carbon build up in the ring grooves which restricts the rings from moving freely and doing their job, resulting in loss of compression. Auto-RX will slowly dissolves that carbon raising the compression of each cylinder. The cylinder with the lowest compression will benefit the most, so you get less compression gap across all eight cylinders, which will make the engine run with less vibration. It's a noticeable difference. With that many miles there will be a noticeable change, and he should comment on it. It does work slowly over a course of 2000 miles.

 

they make a pretty good engine flush, im really not sure what its called, i use it in mine every now and then, drain out the oil and pour a jug of that engine flush in there and it does wonders, or even a few quarts of new oil will work pretty good,

 

I would make sure it has a clean fuel filter and air filter. I would check the fuel pressure. I would also clean the MAF and put two bottles of Valvoline Complete Fuel System Cleaner in a tank of gas to clean the injectors.