I recently replaced my entire PCV system (oil return hose was broken). Car has now never run better. Seems like a new engine almost - amazing difference. Wish I had caught the problem earlier. But the car has since failed the CO 1.10 limit reading 1.58; and the NOX 3600 limit, reading 5600 emissions. HC is within limits.

Previously, the car had been pushing oil up into the intake manifold and it got pretty blackened up in there. The oil pan looked crummy and I'd like to clean up the inside of the intake manifold and the engine. A friend Volvo tech suggested I put in some ATF with my oil and run it like that for awhile. My question to the board is for an opinion on how much ATF - 1 quart or a half quart?

I'm also running the CRC Guaranteed to Pass Emission Test Formula (can't hurt), thru the fuel system, and then draining the oil, right after using some gunk motor flush. I'm replacing a few other parts also.

I'm thinking that perhaps the two years of driving with the failed PCV system might have left some residual crap in the engine and intake manifold and it needs to be cleaned. When the cleaning is finished I'm going to have the CAT tested. It has a lousy Bosal CAT (won't buy one of these again). I hear the after-market CATS only last for one or two years? So, if it fails the CAT test then I will get a new CAT ... in the meantime ...

Btw, we have a 740 and it had a Bosal CAT and all the cleaning and adjusting did not mean jack, it needed a new CAT (failed CO and NOX). But I suppose I have do at least try to do all I can, just in case it ain't the CAT.

thanks for opinions
diyer

My gas mileage was recently horrible ('89 244GL) I changed the three wire O2 sensor with a one wire $16.00 bosch # 11027 (I think, check archives) and it greatly increased my gas mileage. I would like to put on stock three wire 02 sensor when I get the money, but at $16.00 from autozone I can replace this 02 sensor at every other oil change and still be ahead. So why not try a $16.00 O2 sensor. Make a new one wire harnes matching the length of the old one and you will be able to find out if your stock O2 sensor was faulty. If not then you can reinstall your original and you are only out $16.00. My state only reads fualt codes for tyhe emission system for 1996 and newer vehicles so the error generated by the ECU missing the other two wires (the 02 heater wires) on my '89 would pass unobserved. Next i will change my water temp sensor so that ECu has the best info it can have for maximum running. Good luck passing

The ATF in engine oil trick is an old myth that has been around for years. Bad idea. Change the engine oil with engine oil (that sounds reasonable) more frequently if you like, and that will clean the engine internally just fine. ATF actually has very few detergent dispersants in it, and is recommended by no one in the oil industry as a solution to engine problems.
Use a good 10W-30 and be done with it.

Didn't sound like any bricksters are encouraging you to us ATF in your engine oil.

ATF or Marvel oil in your oil will help loosen sludge in the pan, valve train, and oil drain galleys. I've also heard it suggested for breaking loose rings that are stuck in pistons, but I've not seen that tried.

Use a full quart, but only drive the car for a few good warm up cycle trips before draining it back out. I'd say one tank of gas or so. Change your oil filter of course.

I've never put it in a car of my own, but I've known others to use it successfully.

I don't know what ATF does to old hardened oil seals, but I'd worry that it does not do them any good.

"I don't know what ATF does to old hardened oil seals, but I'd worry that it does not do them any good"

Hmmm, I wonder why the ATF doesn't damage the tranny seals?

thanks,
diyer

Well I had better e-test results on a 1993 GM N-body car after 2 years of extremely frequent oil changes (< 1 per month, ~1000km).

It does not hurt to always run with fresh engine oil.

I also know there are many who do not change as frequently as this with acceptable reliability. Your mileage may vary.

Stef
--
Stef -- 1981 wagon B21A SU M46 318000km chrome roofrack

I'd skip the ATF altogether.

Regarding the high NOx, you don't give your car's model year, but if you have the Volvo/Chrysler ignition used on 240s from mid '81thru 1988, it's been said that the V/C ICU's design can cause hi NOx — and that plugging the vacuum line to the ICU can lower NOx production with little effect on normal operation.

I first posted this (with technical details) on 5/21/04 (see original post here. ) At least one person has found that this solved his high NOX problem.

You can see his happy response at success story.

NOTE that he had failed with a new cat, then plugged the ICU vacuum line, put the old cat back on and passed!.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

M/Y is an 89, 240.

diyer

personnaly i wouldnt put atf in the engine....

i presume you have already done the following:-

new air filter
oil change
new spark plugs
new spark wires
new distributor cap & rotor
throtle body clean
checked all hoses for leaks...
checked FRP for presure/leaks..

if so i would remove the inlet manafold and manually clean the inside...cant see how atf in the oil could POSSIBLY clean the inside ofthe inlet manafold, oil doesnt (shouldnt!) flow in there...

my guess is its a load of little stuff as above...

"i presume you have already done the following:-

new air filter
oil change
new spark plugs
new spark wires
new distributor cap & rotor
throtle body clean
checked all hoses for leaks...
checked FRP for presure/leaks.."

Everything except the FPR and TB, but will clean the TB.

"if so i would remove the inlet manafold and manually clean the inside ..."

That's on my list too.

" ... cant see how atf in the oil could POSSIBLY clean the inside ofthe inlet manafold, oil doesnt (shouldnt!) flow in there..."

Actually oil can get in there from a non-functioning PCV system. Been there done that. What I meant to communicate was that I am cleaning both the throttle body, intake manifold, and the engine all separately. The ATF is for inside the engine. TB, etc., will be done by hand with TB cleaner.

"my guess is its a load of little stuff as above..." PPerhaps in part, but I never found all that little stuff to make much of a difference. Its always those lousy aftermarket CATS and lazy O2 sensors invariably. Just my experience with Volvos over the years.

diyer

Well, I have heard of ATF or Marvel Mystery Oil in the Fuel Tank, to clean Fuel Injectors, but have never heard of using it mixed with the Engine Oil.

From my experience owning two Volvos with a B21E and a B21A, Engine Oil does get into the Inlet Manifold.

It might help to give it a good clean, but you may ruin the gasket taking it off.

Just be sure all your Vacuum Lines and EGR or PulsAir System, CAT, Oxygen Sensor are functioning. I would assume that if you have a CAT, then you also have an O2 Sensor. Bosch recommends changing them after 60,000 miles.

The only cleaning using ATF that I am familiar with is introducing some ATF into the vacuum system or intake to break up or "crack" deposits in the head and cylinders. This procedure fairly common with other high milage vehicles and can be found on the net. I have no experience with emissions testing in S.C.