98 Lesabre, need help...

[fedfuzz]

I recently purchased a 98 LeSabre w/ 115,000 miles on it. Car belonged to a friend of the familys mother. Car has sit a quite a bit over the past year. I purchased the car and drove it for 200+ miles problem free and engine sounded as smooth as possible. However, last night while driving down the hwy I heard a knocking noise. I pulled over and looked the car over. When stopped the car would stumble like it was about to stall, oil pressure would drop and light up, and the volts would drop and light up. Car was not leaking any fluids, and there was plenty of oil up on the dipstick. I drove the car home nice a & slow. I originally thought the noise was coming from a pulley, so today I removed the belt and started the car, the noise does not go away. I checked all the pulleys, they all seem to be ok. Noise appears to be coming from the top half of the engine, maybe valve area. I drove it approx. 1 mile and it even quit making any noise momentarilt 3 or 4 times during the drive. Sounds more as it something it hitting/rubbing on something more than a knock. Also when the engine is cold, the oil pressure and voltage remain stable, only when the car gets up to operating temp. do they start jumping. If anyone has any ideal what this could be, please let me know. I am at a loss of what to work on next. Thanks

[maxwedge]

The voltage and oil pressure jump around at a steady speed or idle?, from here diagnosing as knock is impossible as you can imagine. Is the oil clean, not water or fuel contaminated?

[fedfuzz]

Voltage & oil pressure only jump around when engine is warmed up to operating temp. and at idle. If the car is being drove they are both stable with no movement until you stop. They are also stable at idle if the car has been sitting and is cold. Oil was just changed 500 miles ago. It hasn't used any oil, and oil still appears to be new. (Looks like it was just poured out of the jug) No change in color or smell.

[imidazol97]

Originally Posted by fedfuzz

I recently purchased a 98 LeSabre w/ 115,000 miles on it. Car belonged to a friend of the familys mother. Car has sit a quite a bit over the past year. I purchased the car and drove it for 200+ miles problem free and engine sounded as smooth as possible. Thanks

Was the oil a fresh change? Does the car still have dexcool in it? How does that coolant look?

If you changed or do change the oil, look for coolant in the oil you drain out.

The extra slow idle could be an EGR not closing all the way or a coil giving a poor spark to 2 cylinders after the coils get hot.

Is there any possibility you could use a digital camera to make a video with sound of the noise and post it as an attachment here, if that works, or post it on photobucket.com and put a link to it.

There are many experienced readers who might be able to recognize the sound.

[fedfuzz]

The oil was fresh changed. It was changes about 500 miles before I purchased it. Oil still appears to be can fresh with no change in color or smell. Car does Dexcool in it. Coolant still looks at it normally would and the coolant levels have not changed.

It may be a few days but I will try to get a video of the engine sound and post it for you to hear. I didn't make it home with the car, its about 25 miles away, so next time I go down to work on it I will take the camera.

[fedfuzz]

Unfortunately it was the motor. Broken rod, and scared the crank. Luckily I was able to fine a 05 impala engine w just 60,000 miles on it.

[Scrapper]

Originally Posted by fedfuzz

Unfortunately it was the motor. Broken rod, and scared the crank. Luckily I was able to fine a 05 impala engine w just 60,000 miles on it.

can i ask what kind of oil is in it?

[fedfuzz]

If your asking about the engine that blew I have no ideal what kind of oil the previous owner used. They had it changed at a Valvoline quicklube last.

I put Penzoil 5w-30 (Dino) in the newly installed engine. Figure I will run it 800 -1,000 miles and then change it again. I run Penzoil Platinum (Synthetic) w/ Purolator gold filter in everything else I own. Not sure if I will try it in this engine or not since it already has 60,000 miles on it. I prefer synthetic but I am afraid of getting leaks since I don't know what was previously used in it.

[maxwedge]

New synthetics will not cause oil leaks.

[happydog500]

Originally Posted by maxwedge

New synthetics will not cause oil leaks.

My last motor was nice and tightly sealed, no leaks at all. I put in Synthic and it leaked like a sieve. Leaked from every place the motor could leak from. Man did it leak.
This was a couple years a go. When does, "new" synthetic start?

Chris.

[maxwedge]

The new synthetics have had modifiers in them to help with seal issues for at least 10 years.

[happydog500]

Originally Posted by maxwedge

The new synthetics have had modifiers in them to help with seal issues for at least 10 years.

Doesn't work on older motors.

[Blue Bowtie]

I have changed to synthetic on a '96 Lumina (189 V-6) with 142K, a '95 LeSabre (231 V-6) with 124K, a '96 Sonoma (134 I-4) with 89K, three Fieros with between 90K and 138K, a 2001 Impala with 68K, an '88 Astro with 80K, and never had a leak. This was done with the OLD synthetic (Mobil 1) which did not include a special "high mileage" additive package. The Sonoma did lose a head gasket, but that was probably not due to the oil as much as the aluminum head eroding.

All TRUE synthetics (PAO, not the hydro-cracked Pennzoil, Quaker, and domestic Castrol crap) will do is to soften deposits and clean them away. If the sludge is preventing a damaged seal from leaking, the seal may leak. If the seal is not damaged, once the sludge is cleaned away and the elastomer is made pliable again, the seal will stop leaking. If the synthetic exposed a leak that's bad luck, but it almost certainly didn't cause it. I do know that synthetic tends to wick through the smallest openings, and I have found three leaking oil cooler hoses on various vehicles, but no seals, gaskets, or other joints.

[happydog500]

Glad you have success. I'm 0-2 with switching. My friend switched and now leaks just as bad as I experienced.

Sorry, I didn't understand your definition of "cause." If you have no leaks at all, switch to synthetic and it leaks bad, it's not the oil that "causes" the leak.

Since this happens all the time, I didn't want to post on a forum that nothing will happen if you switch.

I wish I could change to synthetic. My friend and I, The mechanic I go to, and the guy on the radio experience it will leak. I'm stuck using Dino oil.

Chris.

[Jrs3800]

I run synthetic with no issues... and have gone back and forth... Synthetics causing a motor to leak is a Myth... The reason they can start to leak is due to all the build up inside the motor being cleaned away.. But newer Dino oils also have better cleaning agents as well so if you have a seep its only going to get worse over time...

3800's love to leak in a few places no matter what oil you use... Rear main from time to time, More than likely to be the rear plate that houses the rear main and seals the back of the block... Oil pan gasket and or valve cover gaskets... One of these will leak during the life of the car no matter what oil you use...

My 95 Bonneville engine had 60k on it when it was installed... I have been back and forth with synthetic and Dino... I have had 2 common issues with it, Valve cover gaskets( $13 ) and oil pan gasket ( $30 )... I replaced those and to this day( Motor has 87,000 on it now ) the motor is bone dry...

My 03 Bonneville ran Kendall for the first 50ish k miles, I then went to Synthetic... It too is bone dry and now at 77,000...

The original motor in the van was changed to synthetic at 170,000 Miles, it too was dry and had no leaks... as well I ran my 91 Bonneville on Synthetic for many years starting at 80,000 miles and had no issues... never even replaced the oil pan gasket, no leaks...

Generally the seals and gaskets would have to be pretty bad to have any issues with synthetic..