My 2010 V10 with 80k miles has never burned a drop of oil between oil changes. I changed oil every 5,000 miles and used full synthetic and Motorcraft filters. I never had a check engine light until a few months ago and it was bank 1 catalyst. I had both banks replaced and the dealer said the truck had to be towed because it would not run. They suspected the exhaust was blocked by the bad catalytic converter. $3,000 later I was back on the road and the truck ran fine. I went in for my 5,000 mile oil change and there was no oil on the dipstick. I was advised to check the oil level every 500 miles and sure enough I'm burning about half a quart every 500 miles. Cylinders 1 and 5 compression is down to 120 psi. I'm being told I need a new engine as opposed to trying to rebuild the existing one. Could the back pressure from the blocked exhaust have caused this failure?

 

1st of all, shame on you for not checking your oil at least every other tank full. Any car can develop a problem, new or old.

My my brother in law is guilty of this and we used to live together and work on stuff together. He has toasted a 1.8l civic and almost a 5.3 2013 Silverado.

Clogged cat. I have had this on a 6.8 excursion when I bought it and it was not immediately noticeable under light throttle driving. Under load of any nature it was a real dog. I can’t believe I didn’t romp on it when I test drove it, but I don’t drive stuff like that.

Symptoms... clogged cat made lots of pinging because of heat. You could have damaged/burned valves from this condition.

Your oil loss may be unrelated. You could have a leak. Or it may be burning it. These motors usually use some oil. Between oil filter Adapter gasket and the rear main seal and whatever is burned slightly, I add about 1 quart every thousand miles.

You may may or may not Have damage from oil loss. The civic I mentioned needed a ring job after being run low.

If you spend so much on an exhaust system for your truck you should find a new mechanic. An aftermarket catalytic converter for that truck shouldn’t be more than $500 or so.

A leak down test should be able to diagnose where the loss of combustion pressure is. Your mechanic may be using his more cautious of judgment with not spending any money on a motor that has been run low on oil.

Depending on your situation you might just be able to run the truck as it is and figure out how much oil it’s actually using. You could monitor that two cylinders that are low and see if it deteriorates further.

It’s possible that the rings were damaged from excessive heat due to the clogged catalytic converter. And it’s possible that excessive oil burning caused the catalytic converter to fail.

There is no perfect answer for this. You could look for a decent salvage yard motor.

I have a spare same mileage motor for my excursion that I bought for $100 and is my plan to use in case what I have grenades one day.

 

If the truck runs fine now you could try going with a syn blend or even dino oil and see if it cuts down on your oil consumption . I ran 5-20w syn blend and I used about 1 qt in 1000 miles, went back to 5-30w and back to 1 qt in 4000 miles.

 

I would do a compression check on all cylinders with a leak-down test to determine if it's the rings or the valves. With the exhaust clogged on one side, and the compression on #1 and #5 being on the same bank, I'd say it's related. Again, check if the valves are bad on that side, and a valve job might bring it right back in line with everything else.

 

I'm being quoted $6,000 for a valve job and am being urged to buy a new engine from Ford instead of repair the existing one. Mechanic sees evidence of oil on the spark plugs.

 

Not sure where you are but your mechanic rate is super high.

Complete used motors around western ny are under $1000 and off broadway mechanics around me would swap it for around a thousand.

Maybe work your way more rural for a recommendation for a second opinion mechanic.

A good machine shop will freshen up a set of heads for a few hundred.

Why cant you run it like it is and see how bad the oil burn is?

6k is a lot of bucks.

 

I'm going to run it like it is with heavier oil and see what happens. The truck runs great with plenty of power and you'd never know there is a problem.

 

I wouldn't go heavier than a 30W oil or I predict you will have valve train failure soon.

 

Sounds like your mechanic doesn't want to work on it, thus the higher prices.

If you need a new engine, or the cost to repair the one you have is higher than a replacement engine, but it's still running, then of course just run it til it dies. Just be prepared for it to die at the least opportune moment.

 

my truck has used one quart per thousand since new. 135k miles. Exactly the same

 

Similar story with me. I switched to 5W-30 right about the time ford updated oil spec for the 6.2. And my truck now burns/uses significant less oil now compared to previously.

 

Mine burned about a quart every 900-1000 miles with full synthetic 5-20. Switched to fill synthetic 5-30 and it slowed down to about every 1500 miles. Going to try synthetic blend 5-30 next oil change. The Ford modular engines seem to have this problem. I had a 4.6 l that also did that and had to try a few different kinds of oil

 

One thing about the V10 - read the service procedure for changing the oil. Put ONLY 6 quarts total. Start it up, let it idle a minute, shut it down and check the oil level. It should be between the two dots. If it's between the two dots DO NOT ADD MORE!

When I first got my '01 V10, I'd make sure the oil was right to the top dot on the stick. It would burn off a certain amount, and then stop right in the middle between the two dots. But I kept adding oil, and it would burn it off.

One day, I came across the service procedure, and followed it. I think it's in the owner's manual too... when checking oil level. Oil use stopped completely.

When I sold my truck to my (ex-) landscaper. the first few days he had it, he came back to me and started worrying there was something wrong with it because it was using so much oil. I immediately asked, was he filling it up to the top dot? He said yes. I said... stop that! It immediately stopped using oil as soon as it dropped halfway down between the dots again



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Another thing to consider is ... synthetic oils may or may not have solvents added to modify the viscosity. As these solvents burn off, of course the oil level drops.

 

I've always added 7 quarts to my 05 V10 and that puts it right between the dots. I have never had to add any between changes.

I tried full synthetic on my 99 V10 and it needed oil added all the time. I finally switched back to plain MC synthetic blend and never had any oil use issues after that. That is the main reason I am not a big fan of full synthetic oils. The standard blend, when changed at the right intervals will let your engine live way past the life of the rest of the truck.

 

Regarding oil changes.......

I've always filled the new filter before installing it then add the recommended total quarts to the pan and start the engine, watching my OP gauge. After a few minutes running at idle shut down and re-check oil level on stick. I'll add whatever it takes if any at all up to the "full" mark. For myself I don't like that short time before oil pressure comes up when the filter is empty.