rogerbotswana
Cleaning Cylinder heads and rockers
Hi Guys… I need real help and advice for you experts….

I have a 2002 Pajero 75W with a 6G74 3.5L V6 engine 24valve…. (Jap import)

In complete blindness I never ever changed the oil for years (totally my fault) and now have a hefty issue.

Essentially my oil pressure light came on and now stays on… I changed the oil which was incredibly soupy…. Have flushed the car out with oil 6 times in a row including using Mitsubishi engine Flush twice… leaving Magnatec 10w40 in the engine.

Have changed the filters of course and also changed the pressure switch twice and proven they both work with the use of compressed air and a continuity tester…. STILL NO OIL PRESSURE (light stays on)

Car runs essentially fine but VERY noisy and “Klackety” from the lifters although oil is quite clean… obviously there is no oil getting into the cylinder head rockers…

So I took the oil filler cap off and stuck in a long Philips screwdriver and twizzled around a bit… out came VERY gunky and semi solid oil residue, very thick and gloopy… to me meaning that no nice oil or engine flush is getting into the the heads, it seems very dry in there…… so they need a real good clean as I think all the small oil-ways must be blocked.

I live in Africa (Botswana ) and a mechanic will cost a fortune and probably suggest a new engine…

What I would like to do is remove the cylinder heads intact without removing the rockers or anything and take a while to clean them with diesel and compressed air until I can assure myself that all is well. Then put them back with new gaskets

I would rather not dismantle the head itself in any way as this may be effected by my reasonable inexperience in working on an engine like this (I do have the tools)

Is it possible to remove the heads and clean like this?.... Will I encounter the need to remove the timing belt or camshafts or anything else? and if so is this ok for a reasonable home mechanic?

Is there a step by step guide anyone knows of to do this?

Any advice is very greatly received

Roger
Re: Cleaning Cylinder heads and rockers
Hoohah! From your description I am pretty sure it is the old dreaded "koffie korrel" problem. The lifter noise you hear is because the engine is not getting oil and is expected. Do not start it again / any more.

If you neglect to change oil, the oil deteriorates to such an extent that it makes a carbon like deposit (which eventually looks like coffee grounds when it gets into the sump) mostly which collects in the valve cover area. This flakes off and ends up in the sump. The oil pump sieve picks it up and eventually the oil pump pick up sieve blocks, preventing the oil getting to the engine.

So first check inside the valve covers for a heavy hard black deposit. If you do find such a deposit then you will have to remove the sump and do what some call a "sump service". I am not sure how easy one can remove the sump with engine in vehicle. You might have to remove the front differential. Once the sump is off, take the oil pump pick up off and check it for "koffie korrels". If there is nothing blocking the pick up you have another problem. Unfortunately you will have to go this route first but I am 90% sure it will be the problem. It is an old problem if you neglect servicing.
Now if you did find the oil pump pick up blocked and while the sump and valve covers are off scoop out as much sludge as you can. Then get a squirt bottle full of petrol with a paint brush and clean the area around the valves washing all deposits down and out the bottom of the engine with large amounts of petrol.

Once you have everything back change the filter and fill with new oil.
Good luck it is a big job. Change the oil and filter again after about 5000km.
rogerbotswana
Re: Cleaning Cylinder heads and rockers
Peterpot

Thats a great answer....

I had already been told that it was likely the sieve on the pickup. I was advised to remove oil drain plug and to squirt 3 full cans of carb cleaner with straw pointing as much as could through drain plug hole at the pickup... as I did that a lot of small coffee particles came out...

still didn't work...

would testing the oil pressure help at all with a gauge screwed into the pressure switch hole?

I have the type that needs the axle (or diff) lowered to get the sump off... no mean feat at home, but will give it a go...

I was hoping for a solution where I didn't have to take the cylinder heads off and muck around with the timing belt so your solution may just be that case. Its DEFINITELY being starved of clean oil at the rockers so I think cleaning rockers and pickup may help.

I guess thats what i will do

Thanks
Re: Cleaning Cylinder heads and rockers
This also happens when one uses an engine oil of a low spec and typical of the problem on VW Golf's. The Golf engine had 3.5 Litre sump and when someone went and put in a low spec engine oil (also the cheapest) and expected the engine to cope (10 000km with 3.5 Litres of low spec oil!!) it would over time develop a deposit would form in the valve cover and the pick up would block from the "Koffee Korrels". Not a fault of the engine nor the engine oil (here GTX took most of the blame) but a case of not RTFB. (Reading The Factory Bulletin!!) - ie the oil spec was too low for the engine.

Do not run the engine with the oil light on, it will only increase the chance of damaging something. Taking the sump off in your case is a "have to do" unfortunately. There is no real easy way around this except removing the sump. Your "having seen some Koffee korrels" just confirms this.

You could take a chance and once the pick up is cleaned and the sump is back on, run the engine on a heavy duty diesel engine oil. Look for an API CG4 or higher spec it would be an SAE15W/40. The diesel spec has a greater detergent effect at cleaning. You would have to watch the oil light and drain and refill about every 1000km. If the oil light came on again it would mean taking the sump off again. This would be risky and maybe only to get it back here where someone could take the valve covers off and clean it for you. Be aware of the risk.
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