GenVibe - Community for Pontiac Vibe Enthusiasts

Son has a 1999 Caravan 3.3L. All of a sudden developed a loud knock - his buddies think it is a valve lifter issue. Assume not a rod as the engine probably would not run. Any thoughts? Expensive repair? I told him not to drive it - have it towed to a shop we use. Lent him one of my cars for the interim.

Lifters are generally more of a tapping or rattling sound. A loud knock would more likely be a rod bearing. It may run for a long time with bad rod bearings.

beemerphile1 wrote:Lifters are generally more of a tapping or rattling sound. A loud knock would more likely be a rod bearing. It may run for a long time with bad rod bearings.

Doesn't sound like a lo cost repair but better than replacing the engine.

beemerphile1 wrote:Lifters are generally more of a tapping or rattling sound. A loud knock would more likely be a rod bearing. It may run for a long time with bad rod bearings.

Agreed!
1999 caravan with 135,000 miles has a private party book value of about $3000.00 (KBB.com). This means (to me) that the car isn't worth the cost of a rebuilt engine replacement. Three years ago my friend was in this same spot with her 180K 2000 impala. The local junk yard replaced her engine with a used engine for $1200.00 complete with warranty (90 days?)
Today her 2000 Impala is running strong at 250K - YMMV.
chiadog

Additionally,
Rod knocks don't generally magically appear. They are usually the result of doing an "engine oil flush" on a high mileage engine or over-revving a worn-out engine. Also changing oil on a used car purchase that had motor honey or STP covering the rod noise. (IMO). I have personally had the misfortune of doing all of these!

Chiadog wrote:

beemerphile1 wrote:Lifters are generally more of a tapping or rattling sound. A loud knock would more likely be a rod bearing. It may run for a long time with bad rod bearings.

Agreed!
1999 caravan with 135,000 miles has a private party book value of about $3000.00 (KBB.com). This means (to me) that the car isn't worth the cost of a rebuilt engine replacement. Three years ago my friend was in this same spot with her 180K 2000 impala. The local junk yard replaced her engine with a used engine for $1200.00 complete with warranty (90 days?)
Today her 2000 Impala is running strong at 250K - YMMV.
chiadog

Additionally,
Rod knocks don't generally magically appear. They are usually the result of doing an "engine oil flush" on a high mileage engine or over-revving a worn-out engine. Also changing oil on a used car purchase that had motor honey or STP covering the rod noise. (IMO). I have personally had the misfortune of doing all of these!

Agree - would be looking for a "junk yard" engine. Son has had vehicle for nearly a year so it isn't the motor honey scenario. Just has normal oil changes. Would be very surprised if he over-revved the engine.

jake75 wrote:Son has a 1999 Caravan 3.3L. All of a sudden developed a loud knock - his buddies think it is a valve lifter issue. Assume not a rod as the engine probably would not run. Any thoughts? Expensive repair? I told him not to drive it - have it towed to a shop we use. Lent him one of my cars for the interim.

Shop mechanic says options are (1) junk it; (2) drive it until it won't run anymore - might be 2 weeks or 2 years - maybe add a quart of motor honey like Lucas Oil Treatment; (3) replace the motor with a junk yard one at a cost of about $2,200, or a rebuilt one about $3,800.

Mechanic says #2 might be best as you can always then can junk it or replace the engine. Also say you never know what you are getting in a junkyard engine.

Seems to be only one lifter for now that is making the noise. Mechanic said it is pretty loud.

If it really is a lifter. I've heard of adding a quart of auto tranny fluid for a short run to clean the lifter. I have never tried it, so I am not sure of specific directions. Otherwise, motor honey is relatively safe and the engine could last a long time.
also get a second estimate on a used engine, $2,200 sounds high.

If it is a lifter just drive. Back in my hoopde days I had engines that the lifters tapped for many years and they were still going when I got rid of them.

Chiadog wrote:If it really is a lifter. I've heard of adding a quart of auto tranny fluid for a short run to clean the lifter. I have never tried it, so I am not sure of specific directions. Otherwise, motor honey is relatively safe and the engine could last a long time.
also get a second estimate on a used engine, $2,200 sounds high.

That $2,200 is the installed price. I have heard that junkyard prices are not the bargains that they used to be. In 1995 I had to replace an engine in a Toyota Celica. It was $1,700 including tax - cost of engine and labor. A rebuilt Chrysler 3.3L is around $2,500 plus tax. Labor to pull old, install rebuilt I guess is about $1,300.