Minor lower cylinder knock

[bradatucf]

My daughter drove her '99 Bravada with a broken water pump. The truck overheated, and now we have a lower cylinder knock. I had the engine checked for leaks (oil & anti freeze) and the engine is fine. The mechanic called the knock minor.

The dealer wants $4500 for a refurbished engine (3year war), but the truck is only woth $4000 (according to edmunds). Currently we are just driving the truck to see how long it will last.

Anyone have any experience with an engine with a minor knock?

[ericn1300]

the dealer price is about twice what you should expect to pay for a rebuilt, not a refurbished engine installed. google rebuilt engines

edmonds is always low. go to kelly blue book Http://www.kbb.com they show your 99 has a private party value of from $6,500 to over $7,000 and the retail price is almost $9,000. check the local listings on kbb.com to see what one like yours is selling for.

[drdd]

Originally Posted by bradatucf

My daughter drove her '99 Bravada with a broken water pump. The truck overheated, and now we have a lower cylinder knock. I had the engine checked for leaks (oil & anti freeze) and the engine is fine. The mechanic called the knock minor.

The dealer wants $4500 for a refurbished engine (3year war), but the truck is only woth $4000 (according to edmunds). Currently we are just driving the truck to see how long it will last.

Anyone have any experience with an engine with a minor knock?

by 'knock' do you mean cylinder detonation ? or just a knocking sound?

[bradatucf]

The mechanic stated 'lower cylinder knock'. When the engine is warm you hear a tick.....tick....tick (like lifters) and when you press the gas hard you hear it more. You only hear the loud knock when you accelerate. Keeping a stead speed you really can't hear it. The sound come from the engine block, if I understood the mechanic.

thanks for any info

[ericn1300]

could be piston slap caused by the piston rings or the piston crank bearing being damaged. did your mechanic do a compression test on all cylinders? that would find any problems with the piston rings.

[bradatucf]

Originally Posted by ericn1300

could be piston slap caused by the piston rings or the piston crank bearing being damaged. did your mechanic do a compression test on all cylinders? that would find any problems with the piston rings.

The mechanic mentioned something about a coating on the rod that has worn off and that is making part of the noise. He stated that the engine could run like it is, or just die at anytime without warning. The engine doesn't burn or blow smoke out the back at all, there is no drips from the engine. I don't really know if the did a compression test. I know that once the water pump was replace they did do some sort of compression test, but my guess is that was on the cooling system.

It is kind of funny, when I mentioned what my daughter did, I had a whole bunch of co-workers that knew someone in their family (sibling, child, themselves, spouses) that had wrecked an engine. I had never heard about it, until I mentioned. It seemed a lot more common than I thought.

[ericn1300]

Originally Posted by bradatucf

It is kind of funny, when I mentioned what my daughter did, I had a whole bunch of co-workers that knew someone in their family (sibling, child, themselves, spouses) that had wrecked an engine. I had never heard about it, until I mentioned. It seemed a lot more common than I thought.

Yeah, ive got a few of those stories too. my sister actually called me on her cell phone and asked what the red oil light means while still driving. with all the sensors and electronics on newer vehicles you'd think they would shut down automaticaly. i was driving my moms car at 80mph when the water pump failed and the engine went over temp. it first shut off the AC and while i was fiddling with that it shut off the cruise control. thats when i finaly noticed the guage and pulled over in time. i guess just shutting off the engine would be too dangerous, sudden loss of power brakes and steering could be a bigger problem. i'd rather have a big mechanics bill than a bigger hospital bill.

i wouldn't be taking any cross country trips with the engine knock but go ahead and drive it until it dies. you might be able to get away with a "short block" replacement where you salvage the heads, intake manifold and fuel injection and just replace the lower end. do a google on short blocks. i got over 308,000 hits when i tried it.