Cylinder Washdown?

JEEPTHIS · Jan 4, 2005

A friend's 89 4.0 wouldn't start. I know, it could have been anything. He replaced just about every sensor, checked fusable links, etc....... He then checked with a jeep mechanic who said the cylinders may have been "washed down" form flooding the beast. By adding approx. 8 oz. of oil into each cylinder it fired right up and fouled the plugs. He put new plugs in it and it fired right up and runs great again. Anyone else ever hear of this??

sidriptide · Jan 4, 2005

JEEPTHIS said:
By adding approx. 8 oz. of oil into each cylinder it fired right up and fouled the plugs.

8 OZ!?!?!?! thats alot of fuid to put in a cylinder that is going to try to compress everything inside of it!! i would be careful that it didnt hydro-lock and break valves/pistons/cylinder walls.... i have never heard of puting oil in the cylinders to absorb the fuel.. pulling all the plugs out and disconnecting the coil wire and spinning the engine with the starter will generally "clear" the intake/combustion chamber of excess fuel and let it air-dry for a short time and button it back up.... maybe a squirt of oil from an oil can into the cylinder but no way 8 oz... i'm suprised you didnt hurt the engine.. if it worked, i guess theres some kinda truth behind the theory..

Click to expand...

tompatjr · Jan 4, 2005

JEEPTHIS said:
By adding approx. 8 oz. of oil into each cylinder it fired right up and fouled the plugs. He put new plugs in it and it fired right up and runs great again. Anyone else ever hear of this??

How did you add the oil? Also you seem to say 8oz into each cylinder...is that correct? 6x8=48oz oil used

Anyway, I have always heard that washdown is a condition where gas or other fuel washes away the protective oil coat away from the cylinder walls. This leaves the walls and piston unlubricated and causes increased wear or in some cases galling. I would also think that washdown would cause a loss of compression which maybe what happened.

JEEPTHIS · Jan 4, 2005

Sorry, I meant 3 oz.(typing with the hunt and peck method) The compression on the cylinders prior to the oil were 165,170,180,175,170,175 so that should have been good enough. They did go up a little bit after they were checked after the engine fired up. I just thought it sounded weird and wanted to share it with all.

tompatjr · Jan 4, 2005

JEEPTHIS said:
Sorry, I meant 3 oz.(typing with the hunt and peck method) The compression on the cylinders prior to the oil were 165,170,180,175,170,175 so that should have been good enough. They did go up a little bit after they were checked after the engine fired up. I just thought it sounded weird and wanted to share it with all.

3oz still sound like a lot of oil per cylinder, too me! I guess I should correct myself about the compression loss. Adding oil would increase the compression a marginal amount.

If you flooded the engine, then removed the plugs and did the oil trick then that may have allowed wet (fuel soaked) plugs time to dry. Seems wet plugs won't fire. Could have been as simple as drying the plugs.

sidriptide · Jan 4, 2005

something still doesnt sound right though.. this sounds like a troubleshooting exercize that ran over quite a length of time if all the sensors were replaced. and if it were just a case of the engine being flooded all it needed to do was sit for 15-20 minutes and "dry out".. sounds like genuine XJ-NO-START to me.. which often cures itself and is very hard to pinpoint... quie possible the oil had nothing to do with it at all and was just a coincidence.. how "qualified" was this mechanic who suggested this anyways?

JEEPTHIS · Jan 4, 2005

Certified Jeep mechanic (retired), take that for what it's worth though. And in response to simply flooding the motor, it sat for two weeks while parts were changed etc... As a matter of fact, for three days it sat in a heated garage while they were away.

Ed in North Ga. · Jan 5, 2005

That almost sounds like he wanted to prevent a dry start- Ive never heard of anyone jumping in and starting it right after putting in oil and plugs though.

We used to do this on old cars that have been sitting for years- fill up the cylinder with oil and let it soak down for a few weeks, then hand turn the engine with the plugs out, then start(or try to start) her.

Flyfisher · Jan 5, 2005

Washdown? I've heard of it...from flooded vehicles in VERY cold weather. Used to work at a gas station while going to college in Bozeman, Montana in the 80's. When temps got really cold (below -20F), folks would flood engines trying to start them, run down their batteries, then call us for a jump.

If engines wouldn't start right away, we'd tow them to the garage, do an oil change, then they'd start right up. Reason? Seems the excessive flooding put a lot of gas into the oil sump...preventing adequate compression. With new oil, engines would start.

Just thought I'd add my 2-cents...

Cylinder Washdown?

JEEPTHIS

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sidriptide

nobody of any consequence

tompatjr

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JEEPTHIS

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tompatjr

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sidriptide

nobody of any consequence

JEEPTHIS

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Ed in North Ga.

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Flyfisher

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