Sludge problems

[tiagoncalves]

Hello. My old Renaul 4GTL is full of dark sludge in the engine. My quilometer counter as stoped a few years ago, and maybe I have missed the proper oil changing. Is this a big problem? And, there is a way to solve it? Thanks.

 

[DavidN]

I had the same phenomenon with my R4 F6 engine.
But that engine was out of use for 9 Years!

I "solved" it the following way...

- Open the oil drain plug and let as most of the crap get out of the engine as possible

(I left it open for 2 days. To warm the engine up could help, but I would be careful not to operate it with that sludge inside.)

- Remove the valve hood
- Get you some Diesel fuel
- Clean everything around the valves (and especially the inside of the valve hood) with Diesel and a paint brush
- Remove the oil filter
- Clean with Diesel and brush as far as you can get into the oilfilter mounting on the side of the engine
- Mount a new oil filter and a new valve cover gasket
- Close the drain plug
- Fill the engine with 3 litres Diesel
- Pull the "main" ignition cable
- Crank the engine without pulling the choke or hitting the pedal until there is oil pressure (watch the warning light)

(To make the cranking process easier for the starter you can also remove the spark plugs.)

- Repeat that a few times but let the starter engine cool down before every attempt

DON'T let the engine start!!!
We want it just to crank, NOT to run!
That way the Diesel can flush it without doing any damage to the inner bearings.

- Open up the drain plug again and let all of the Diesel-crap-mixture get out
- Refill with fresh oil

I would suggest not to wait too long with a second oil (and filter) change after using this method.
(Ideally you do this when the engine is thoroughly hot.)

Good luck!

David

 

[tiagoncalves]

Thanks for the reply. My 4L runs continuously for about 5 years, it has just stoped the last 3 months for some repairs in the painture. I've noticed the sludge in the engine, and would like to fix it. I post a photograph for you to see how it is. Does it look very bad? I'm using the 4L now...
So, I have to remove the valve cover, right? ok, I'll try it.
Let me see if I understand it: I remove the spark plug and fill the engine with diesel. Then I push the key, to let the starter run?
Any more recomendations?

Thanks a lot!

 

[reggie]

just buy a tin of engine flush poor it in - run it for 15 mins on tickover - drain oil and change filter - fill with new oil- job done.
Reg

 

[tiagoncalves]

Hi. I've used the engine flush, and have make like the instructions. I just leave the product in the engine for 3 min, as they said. But it hasn't clean a lot... Any sugestion?
Also, when the engine is running, it doesn't look like the oil is reaching the top of the valves. Should I see the oil spliting all over, when open the oil cover? How can I see if the oil pump is running like it should?

Thanks a lot again.

Tiago

 

[reggie]

black death

on your picture you can see the hole on your rocker arm on the left is open and clean so you dont have an internal problem - so no need to worry - also dont wash all that gunge off it will go down your push rod tubes and block your oil pick up then you are in trouble - just change your oil more often - it will clean itself slowly. i feel qualified on this subject i started at renault main dealers in 1969 lets say 2 oil changes a day for 40 years i will let you work out how many that is, its a bit like a shiny black chassis - looks very nice - but its whats inside that matters especialy at the front where the chassis legs fasten to the floor pan - you need to look inside - either use a camera or cut it open - so i dont think you need to worry about your engine - 7 out of 10 have a bit of gunge
reg

 

[pepper]

I'd say the same as Reggie, I'd never use a flushing agent in a clogged up engine, it will cause you more trouble than you think! It will loosen all the gunge and it will end up blocking all the oil ways!!

On the one and only car I did this too, it had had lovely oil pressure for a 200,000 mile engine but I decided to pop a bottle of engine flush into it before a service, ever after the poor things oil light would come on at tickover and as it was a Volkswagen it had a nasty little buzzer to remind you too!

Never ever again for me.