Outer Limits 4x4 Board

Another valve lifter story... Or is it?

My NL (nearly 200000 km) has the death rattles when you start it up. I assumed it was valve lifters. I have used additives, but no real difference. New oil does the job for 1000 km or so and then it is back to the rattles on startup. Not consistent either - hot or cold.

I read on a magna forum about the hydraulic tensioner. Does the 6g74 have a hydraulic tensioner. If so, maybe the noise is something to do with that?

When the car was newer, it used to develop a clatter when towing my caravan up a long hill and the thermal valve was cutting in to bypass some oil through the oil cooler in front of the radiator. The noise was similar to the cold start situation I am mow experiencing.

Many years ago, I had similar noises on cold startup in a Triumph 2000. It was the oil pressure relief valve blowing off. Maybe this is doing the same thing here?

Any comments?

Not an answer to your question sorry but am interested about the comment re the oil cooler. Does is not circulate oil all the time?

Does the oil cooler circulate all the time? - as far as I know, No. I have read somewhere that there is a temperature sensor which, when the oil temp gets above a certain value, opens a valve and oil circulates thru the cooler. Certainly this seems to be the case with mine. I cannot find any info about it in the useless Haynes manual - same with a knock sensor - no info.

Most of the time, the oil cooler is cold, but if you tow a load up a long hill and stop & put your hand on the cooler, it is HOT. This was the only time the clatter ever came on, and it was loud. If I kept the revs below 3000, it wouldn't clatter, above this and away it went. Needless to say, I kept the revs down until I got to the top of the hill and the noise went away as the oil cooled (and presumably the cooler flow was stopped).That is why I thought it was related to oil pressure. Now the engine is older, it doesn't clatter any more.

It makes sense that the oil cooler wouldn't flow all the time. You need to get the oil temp up to help in flowing around the engine, and more imnportantly to avoid creating sludge. Have you ever seen a car engine which runs short runs only in cold climates? they get very sludgy inside, whereas a warm engine rarely gets dirty.

Hi Date,

Now that you have made me think about it, yes it would make sense not to be always circulating. I know you want to keep the oil nice and hot for circulation and pressure.

I have seen underside oil caps and things on cars that just do short runs, the condensation builds up and it looks like blown head gaskets when in actual fact all the vehicle needs is a decent run.

Glen

Yes once the oil heats up a bypass valve opens up to allow oil to circulate through the oil cooler.
It's a spring loaded poppet like valve located just in front of the oil filter where the oil cooler lines run into.
Re the tappet issue I would be trying a few different oils the see if it makes a difference.
My 3.0 used to do this until I used Slick 50 additive and it never did it again. The oil drain holes in the hydraulic lifters are very small and can easily gunk up leaving them full of oil.
There is a bleed down procedure for these here :-
http://www.4x4wire.com/mitsubishi/tech/ ... ter_noise/

Bitsamissin wrote: There is a bleed down procedure for these here :-
http://www.4x4wire.com/mitsubishi/tech/ ... ter_noise/

Thats exactly what the older Evo(Lancer) engines get, they just gunk up over time, I used some stuff made by Promar on my Evo and it came good after one change.
I am not sure if it is an option but with the evos you can swap out the lifters for newer gen ones, which have a much larger hole.

http://www.vfaq.com/mods/lifters.html

Down the bottom it has a blurry pic of the 1st gen and 2nd gen lifters.

Yes I also heard they changed them for the Pajero's as well.
3.0 & 3.5 V6 DOHC all had this issue at times but by the time the NL 3.5 V6 SOHC came out they changed the lifters so it's a much rarer issue.
I was told that the lifters are basically the same but with larger holes so they are less likely to gunk up.
A mate of mine had this issue in his NJ 3.5 DOHC it drove him nuts and no matter what he did he couldn't get rid of the noise. He eventually spent $1600 getting them all replaced (all 32) with the newer type and has never had a problem since.

Yeah I have always just used it as a gental reminder to change my oil as it doesnt come on till after about 5,000+ kms.