Cracked Piston Replacement

Question:
It’s a lovely site and easy to understand for people who are not mechanically inclined. My garageman said one of the pistons is cracked and therefore he must change all the pistons. Is that true? Why not just change the one that’s cracked?

Thank you,
Mrs. A

Answer:
It is general practice to change all the pistons at once. If one piston is cracked, there is a good chance the others will crack in short time. When replacing the piston, the cylinder walls sometime need to be remachined, and at least honed, to allow the new rings to seat. It is important for the rings to seat properly or your engine will not have good compression and may burn oil. The labor to replace one piston or all of them is not much more, and the pistons are generally purchased in sets, so his advice to replace all pistons is good.

Kevin

Posted: 11th May 2006  |  Author: Kevin Schappell  |  Category: Engine

Oil Change Disaster

Dear Kevin,

I am a Los Angeles Superior Court Mediator and I was hoping that you could help me with a technical question I have regarding a case I am hearing?

The case involves a litigant who took his car in for a 7-10 point check and a regular oil change (this being done before a long weekend driving trip). The party picked up his car, drove about 10 miles to his home and packed up the car and then drove on the freeway about another 20 miles until the car died. Knowing a little about cars, he checked the oil and it was bone dry, he proceeded to purchase 5 qts of oil and put it into the car, which took all 5 quarts. He then tried to start/run the car to no avail. Then had it towed and filed suit with our court.

My understanding is that the car would not have made it 1-2 miles without oil, not 30+? Is this true. It was also a cool evening (if that matters).

The car is a 1977 Pontiac LeMans (a classic and am told not many were made). The plaintiff also had the engine rebuilt just 5 months prior and it seems now, with some of the testimony I have in, that the engine needs to be rebuilt again.

Does any of this sound correct to you? I respect your opinion. The trial is Thursday so time is of the essence.

Thank you.

Respectfully,

Peggy R.
Court Mediator

Answer:

There are three possibilities that may have caused this situation…

1. The oil filter was not tightened properly and the oil slowly leaked out or

2. the gasket from the old oil filter was left on the engine, and when the new filter was installed, it caused a leak due to having two gaskets instead of one.

3. The drain plug was not tightened and fell out a few minutes before the engine seized. Any of the scenarios should be able to be proved by inspecting the underside of the engine looking for fresh oil indicating a leak, or a missing drain plug.

If the shop forgot to put oil in the engine, the car would not have made it more than a mile.

When doing an oil change, the mechanic should start the car, check for proper oil pressure (either on the oil pressure guage if installed, or by the absense of the oil pressure warning light) and check for leaks. Then check oil level after the engine has run for a minute or two.

Unfortunetly I have heard way to many stories of loose drain plugs, or loose oil filters from quick lube shops.

Take Care,

Kevin Schappell

P.S. We have a list of Online Oil Change Coupons updated daily for those visitors who use a mechanic for their oil changes. (Nothing wrong with that!)

Posted: 5th May 2006  |  Author: Kevin Schappell  |  Category: Oil & Lubrication

Scratches after washing your car

Question:

Hi Kevin,

Your web site is fabulous – I googled “car washing” and your site was in the top three that came up. I have just spent 40 minutes reading through your various pages – great information.

Here is my question. I have a 2005 Fire Red Mustang, that just got its first wash after a few months of winter driving (I know, very bad to wait so long!). It is a lovely spring day in Vancouver and so I washed all the grime off my car. Some of the black tar like grime was very stubborn, and so I used the abrasive side of one of those two sided dish washing sponges to give them a good scrub. Not so clever as I discovered after I dried the car, now I can see whitish scuff like hazing in the paint where I did this.

I am hoping that all I did was scrub off the wax. I intend to leave the car in the garage over night to completely dry, and then wax it tomorrow – do you think this will remove those nasty scrub marks?

I hope I haven’t ruined my paint.

Thanks for your help.

Sandy

Answer:

Sandy,

You probably scratched the clear coat, which can be fixed. I would take it to a body shop and have them look at it, as it’s not an easy job for the beginner. They will probably use a cutting compound to smooth out the scratches, and then polish it to bring back the shine. I would not tackle the job yourself, as you may break through to the base color, then the only way to get the shine back, would be to respray the clear coat.

Good Luck,

Kevin

Posted: 5th May 2006  |  Author: Kevin Schappell  |  Category: Body, Car Care

Water in gas tank

Question:

The gas door and cap were accidentally left open when going through a car wash. The tank had just been filled up and it looks like there is a metal door that is closed unless a fuel pump is inserted. What problems may occur and is there something that should be done?

Karen

Answer:

Karen,

I would put a bottle of “Dry Gas” or similar gas line treatment that removes water, into the tank immediately. The alcohol in the treatment removes the water from the gas tank. If you experience sputtering, or poor performance after the treatment, I would have the tank flushed at your mechanic. More than likely, not much water entered, since the tank was full, and the flap in the filler neck should have prevented some of the water from getting in.

Kevin

Posted: 5th May 2006  |  Author: Kevin Schappell  |  Category: Fuel

Valve Seal Replacement

Question:

There’s a good chance I have to replace my valve seals on my ’98 Jeep GC – 5.9 since I am using up 5 qts of oil in about 4-5 mos, no leaks nor smoke except at start-up. How much damage am I causing by not repairing it ASAP ?

How much does a repair like this cost ? Am I better off going to a dealership or a private mechanic ? Everyone knows dealerships will charge an arm and a leg and your 1st born.

Thanks for taking the time to answer.

Regards,

Tom

Answer:

As long as you keep the oil level up, I would not be too worried about the damage being done to the engine. You may be wearing out the spark plugs a little sooner due to having to burn that oil and the deposits left on the plug. I would estimate between 4 and 8 hours of labor depending on how involved it is to get to the seals. If it is an overhead cam engine, expect a little more time, but I believe the 5.9 is a V-8 with the camshaft in the block. The seals themselves are usually very cheap and the expense of the job is mostly in the labor.

Good Luck,

Kevin

Posted: 5th May 2006  |  Author: Kevin Schappell  |  Category: Engine, Oil & Lubrication

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