My 98 has 140,000 miles on it and i just switched over to syn oil. ever since i did that i have went through more oil than i could ever have imagined. Also at higher speeds, 60-80 i hear this clicking sort of noise coming from under the hood, not all the time though. the rpms stay the same and i dont notice anything otherwise. I just dont understand where the noise is coming from or what caused it. do you think it has somthing to do with the oil possibly. i check the oil once or twice a week, so it is rarley low. this noise boggles my mind. at first i thought it was the fan hitting the shroud, but it wasnt. any suggestions will be greatly appreciated.

 

What weight oil are you using? Most of the synthetic stuff is 5wXX (I've even seen 0wXX) meaning it's pretty thin. At 140k, the dino oil you HAD been using (undoubtedly 10wXX) was thick enough to not slip past rings and seals. I've been running straight synthetic 5w50 since 5000 miles (I'm at 86k) and I've only changed it 4 times. I use maybe 1 quart between changes. There's nothing wrong with synthetic, but on a worn engine, it will really show where the wear is.

The clicking might be the lifters clicking. They depend on oil pressure. If they're worn and the oil's thinned out ... I don't know ... just a thought.

You might want to go back to dino oil ... 20w50 ... or try 5w50 synth ... or experiment with some thickener ... motor medic or motor honey or whatever they call that stuff.

 

or maybe try a 20-50 synthetic blend, thats what i use with 120,000 miles. a little thicker, and not pure synthetic but the truck seems happy with it!

 

Last 2 rebuilt motors I have had (one V-10 dodge and one 350 chevy) I ran synthetic after 20,000km on and both motors didnt make 40,000 kms. [:@]

I personally have had nothing but bad experience with synthetic oils and will stick to conventional oils from here on out.

Up here in the north there are a few people that run the 0W30 wieght synthetic come winter time for those hard starts and for when the weather reaches the -40C we are known for. One perticular vehicle is a 99 winstar that has over 525,000 kms on the original motor. It gets the synthetic treatment along with the owners other 3 vehicles during the fall till the early spring. Other wise its 5w30 dino oil the rest of the year.

 

your confusing me a little bit here... ever since you did the switch you have went through more oil then ever,,, then again you check it regurlarly and its rarley low... what im asking is .. is your motor consuming oil? do you have to add more then a quart between oil changes?

the ticking may be a ping,. or lifter/rocker chatter.. easiest way to check is to go back to your original oil and see if it changes... synthetic can be a blessing if used right.. its not rocket science... but with a motor that old (miles wise) i would suggest converting to syn slowley... start with a 75% dino and 25% syn blendd. then 50/50 then 25% 75% then full 100% (respectively) if you choose so..

and im assuming you have gone through a motor change or rebuild... your sig says 255K and you advertising 140K in your post

 

I think the 255k is on his 94. The 140k is on is 98. It's still quite a few miles to start running straight synthetic.

Spike7ss: I've run over 86k miles on this truck using straight 5w50 synthetic, changing the oil about every 2 years (The first 5k was on the factory junk). I run a dual, oversized filter rig and burn 1 quart about every 12k or so. Motor's running strong. Haven't had to do a thing to it ... well ... I changed the belt once.

I don't really feel like trying to convert km to miles but 20k on a rebuild doesn't sound like much. You sure it was the oil?

 

I've done the same as Spike-------- 0w30 blend--but it's on my 2001 neon.
The car had a knock at start up. First change of the 0w-30 blend no more knock.

Cheers
kayakman

 

Synthetic Oil will release any built up sludge in a older engine. If you have decent filtering then that shouldn't be much of an issue however there is a chance that some may have gotten into a pushrod causing to clog the flow of oil into the lifter valley which may have caused the noise you are hearing. It always a good idea when switching from dino to synthetic is to do a flush with AutoRx or similar product to clean the engine throughly. Sometimes high mileage engines need more then one application of the flush product.

 

or a cap full or two of atf fluid about 50 miles before your oil change,,, my grandpa tought me that ... atf has ALOT more detergent in it then motor oil does and it really helps to break up that sludge


his 88 nissan pickup ran for over 370K before the body rotted out so bad it wouldnt pass inspection

 

i put 10w30 synthetic into my truck at my 100k km oilchange,. i'm nearly 104000 now and i must say i hav't had any complaints, its still running smooth, and i hav't burnt/used any excess oil.