Diagnosing coolant leakage in oil

[André4Renaults]

Hi

Have a look at the gasket to see if there are any breaks/ overheating damage to the gasket. If so, you can eliminate the liner seals from your investigation. It is imperative you do not turn the engine whilst the cylinder head is off as you will disturb the liner seals and give yourself more work. You mentioned some loose bolts, this could also have been the cause of the problem.

Place the bolts and big washers over the liners as soon as possible to avoid them moving! The loose bolts sound suspicious to me....... Careful examination of the remains of the head gasket might reveal some clues... It sounds (and looks!) like a job for "those little grey cells"!

 

[JdeW]

Cause for the loose bolts could be that they weren't tightened for the second time.
After replacing the head gasket the bolts are tightened for the first time to the correct amount of torque.
Fill up all fluids, start the engine and let it run (stationairy) until the fan kicks in.
Stop the engine, let it cool down and then again tighten the bolts again to the right torque.

 

[jack23247]

In the excellent instructions given, disconnecting the negative lead from the battery (assuming the car is negatively earthed) hasn't been mentioned - it's not specific to the job - but is a good idea safety wise.

No worries, I did so when removing the coolant hose!

Hi

Have a look at the gasket to see if there are any breaks/ overheating damage to the gasket. If so, you can eliminate the liner seals from your investigation. It is imperative you do not turn the engine whilst the cylinder head is off as you will disturb the liner seals and give yourself more work. You mentioned some loose bolts, this could also have been the cause of the problem.

The gasket seems (to my untrained eye) to be in good condition. There is some crust between cylinder #2 and #3, but it's not discolored. The only problematic area seems to be the portion left of #1, which had a lot of accumulated sludge on it.

 

[jack23247]

Place the bolts and big washers over the liners as soon as possible to avoid them moving! The loose bolts sound suspicious to me....... Careful examination of the remains of the head gasket might reveal some clues... It sounds (and looks!) like a job for "those little grey cells"!

I had to fetch shorter bolts from the local hardware store, can you tell by looking at the attached pictures if I did it correctly? I sure hope so.


As for the gasket itself: the portion around #1 is caked with oil, while the rest seems fairly clean. The head detached very easily from the block (it startled me!) and as soon as I undid the aforementioned bolts (#7 and #9 are the top and bottom leftmost respectively, while #5 is right of #7) a lot of coolant spew out. Bolt #10 (top right) was somewhat loose as well, but not as much as, say, #9.

Regarding the pistons: cylinder #1 is full of water, #2 looks very clean, #3 has a lot of carbon buildup (can't see the markings on the piston) and #4 does as well, albeit to a lesser degree. I drained what I could from #1 with paper towels and it was mostly clear coolant, but as you can see some of it is still there. I didn't want to risk moving the liners so I didn't do anything else.

I took a brief look under the head but I didn't see much as I did not turn it upside down, as I'm not sure if it's safe or not to do so.

I think I should remove the gasket next and clean the mating surfaces, but that would require undoing the bolts that secure the liners. Also, my brake cleaner won't arrive until monday so I have some time to think it over carefully.

 

[jack23247]

I have the impression this engine's not been serviced for some time! Never fear, diesel is a good liquid to shift any sludge that's accumulated in the rocker area and in other places. Another good fluid that might help is flushing oil. Most decent auto-shops should stock it and you use it by firstly warming the engine with the existing oil, then drain it out and put the sump plug back. Now put the flushing oil in the engine to the right level on the dipstick and allow the engine to idle at tick-over for about 15 minutes. Now drain this out. This might to shift loads of crud from the engine's pipes.

Thanks for the suggestions! The thing with this car is that it's been daily-driven for a short while, then it sat for a while due to a slew of problems, then it's been driven again, then it sat again, and so on... this was until you guys helped me nail down the issue to the missing support bracket. Since it's racked up so few miles, my mechanic never thought about changing the oil in the various times I brought it to the shop. We were supposed to do a full fluid exchange the last time I brought it in but I decided to take it home and test drive it for a while to see if the issue was finally fixed and then this happened.

Here's a closeup of the area around cyl#1, taken after I had already removed most of the coolant from the cylinder and some of the sludge from the gasket.

 

[JdeW]

I had to fetch shorter bolts from the local hardware store, can you tell by looking at the attached pictures if I did it correctly? I sure hope so.

It's better to remove the gasket and then secure the liners with 10 bolts and washers. As long as the engine doesn't turn there's no problem.



You can start by cleaning the mating surfaces, just remove the bolt/washer where you want to clean and place it back, again as long as the engine doesn't turn everything stays fine.

The head itself is just a lump of aluminum with the rockers and valves and can be handled in every direction.

Furthermore I would start cleaning everything where you can, draining the coolant and oil etc.
And do as @André4Renaults wrote with flushing the engine with diesel or flushing oil as there might still be coolant remains in oil channels.

 

[angel]

Discoloration or pitting of the head gasket compression ring means leakage. Ring should be bright silver, and also its imprint on the cylinder head face should be even and have a width of 1,5-3mm.
Compression leakage to water jackets and/or water leakage to combustion chambers usually happen before oil/coolant mix on an engine with a blown head gasket.

 

[jack23247]

Hi all, a few updates: I have taken off the head gasket and it's not pitted, except for a small portion between the liners of the middle cylinders, where there seems to have been some previous damage.

Here's a closeup of the interested portion of the head, the pitting is definitely noticeable. The bluish-gray portion in the middle is leftover material from the head gasket. This portion of the head was fairly dry and no oil residues were present.

Here's a photo of the cylinders and liners with some areas of interest highlighted.

I - The area where the coolant leak supposedly was. The compression ring was completely caked in oil/coolant but does not seem to be discolored. I'll take some more pictures after degreasing. The inner walls of the liner have some spots, possibly due to the water intrusion. They can't be felt by touch but can be clearly seen, I'll take some pictures next time. Also, cylinder #1 was completely flooded.
II and III - The liners seem to touch each other here, not sure if they're supposed to...
IV - There seems to be some discoloration here, but the cylinder was completely dry.

The head is now sitting in brake cleaner, and I am planning to remove and service the water pump next, as it's quite dirty and the pulley does not move freely. I have also secured the liners with all ten bolts as instructed.

 

[André4Renaults]

10/10 for your cylinder liner clamping! Looking at the pictures cylinder one seems discoloured and your remark that the bore was full of water suggests this is the cause of your original problem. Once the head is cleaned up I'd suggest having it examined by an engineering workshop, who can confirm if it's "true" or not. Maybe they'll assist in rebuilding the head, and having gone to the trouble of removing it I'd be tempted to have all the valves and seals checked and, if necessary, re-ground and vacuum tested. Listen to their advice-it'll be time and money well spent!

 

[jack23247]

I'll find a shop that will check my head and refurbish it if necessary. +1 on the valve seal checkup, they are full of carbon deposits. I haven't tried the soapy water trick yet to check for leaks though.

Regarding the water pump... it does look a bit sad to me. The impeller is quite rusted, the gaskets are shot and the shaft does not move freely. I'm not sure whether it'll be worth it refurbishing it for now.

 

[André4Renaults]

Looking at the picture of the pump I should say it's had it! If the shaft's not moving freely then the bearing's "gone the way of all flesh" and would probably cost more to repair than the cost of a new pump. It would seem a pity to "spoil the ship for a hapeth of tar", so I'd advise a new pump (and I promise to avoid as many clichés next time!)

 

[jack23247]

Yeah I totally agree, better change it while I'm at it. And keep it up with the clichés, they are quite amusing!

A summary of what I am planning to do next:
- Get the manifold off of the head, check for leaks, find a shop to refurbish the head and tune the rockers
- Flush the block and the sump with Diesel to remove some of the sludge
- Clean the mating surfaces of the liners
- Hose down the cooling system to remove as much debris as possible while I'm at it
- Get a new water pump with bolts and gaskets, an oil filter, an air filter, and a head gasket
- Either get the carburator cleaned professionally or do it myself
When everything is done, I'll get a torque wrench and rebuild the engine following the shop manual. I am still using RTA for the moment but I am trying to locate an used Haynes manual. I'll get a digital version of the Haynes later if necessary.

A summary of what I'm planning to do when the engine is back together:
- Fill the cooling system with distilled water and sodium bicarbonate and the oil reservoir with 50% Diesel and 50% Oil
- Run the car at idle until the fans come on as @JdeW suggested
- Re-tighten the head bolts, flush the oil/Diesel mixture from the engine, change the oil filter and fill up with fresh Oil
- Drive ~500KM, flush the oil and the water/bicarb mixture, check the tightness of the bolts once again and fill up with a proper coolant mixture and good quality Oil

Feel free to point out any potential problem with this plan! I am somewhat concerned about cleaning the liners as I'm afraid to scratch them, but the carbon buildup is too much. Also, can the rockers be tuned while the head is off the engine? Can I clean the carb without messing it up by myself?

 

[angel]

You cannot set rocker arm clearances with the head off on any OHV engine (camshaft in block). What's more, whenever you retighten the head bolts, rocker arm clearances need checking, too.
Don't worry about moving the liners when cleaning them, it's really not that easy on an engine that is not freshly reconditioned.
My advice before fitting the head gasket: spray it on both sides with something like this:

Permatex® Copper Spray-A-Gasket® High-Temp Sealant, 12 OZ - Permatex

www.permatex.com

 

[André4Renaults]

You cannot set rocker arm clearances with the head off on any OHV engine (camshaft in block). What's more, whenever you retighten the head bolts, rocker arm clearances need checking, too.

+1 As Angel says, let's clean up the head and have the valve guides (that's the part of the head that allows the valve to slide up and down) together with the valve seats (that's the part of the head that the valve comes into contact with every time is closes) refurbished first. Re-setting tappets is a job to be done once the car's back together.

Cleaning out the "gunk" from the engine's innards is an excellent plan as well. Although this is easier to do when the engine is warm, you can still do it with a cold engine. I would unscrew the oil sump plug and allow the old oil to run out over a day or so; it will run slowly, but it will run out. Then replace the sump plug and add a little diesel or flushing oil into the sump via one of the oil pathways in the block. Do ensure you use the right pathway, or you'll end up with diesel in the water pathways!

 

[jack23247]

You cannot set rocker arm clearances with the head off on any OHV engine (camshaft in block). What's more, whenever you retighten the head bolts, rocker arm clearances need checking, too.
Don't worry about moving the liners when cleaning them, it's really not that easy on an engine that is not freshly reconditioned.
My advice before fitting the head gasket: spray it on both sides with something like this:

Permatex® Copper Spray-A-Gasket® High-Temp Sealant, 12 OZ - Permatex

www.permatex.com

Thanks for the heads up and the advice, I'll definitely get the copper sealant for the gasket.

Yeah I was afraid of that. I'm going to need a feeler gauge or something like that for adjusting the rockers, I guess.

I have since cleaned the surface of the liners and drained the old oil. Next up is Diesel washing, cleaning the cylinders from all the carbon deposit and debris, and I guess I can give the exhaust manifold a good scrub.

Here's how they look after a good scrub. I really can't remove the more stubborn gunk with the plastic tools I'm using now, so if you think I need to be more aggressive I'll need some pointers on what kind of tool I can use.

 

[André4Renaults]

Don't go mad with aggressive cleaning, as you may cause more damage than you mean to. Once everything is back together and running properly a great deal of the "muck" will burn off if the car's taken on a few long runs. Remember a car is, in many way like one's body and needs regular exercise; sitting around and only doing small walks (short slow runs, in vehicular terms) aren't good for one's body or one's car. A steady run along a motorway at a steady 50-60 helps "clear the tubes" so will help a lot when you have the chance to go for long run.

As regards the tappet settings, torque the head bolts to the required settings, then adjust the tappets clearances. Now drive for about 350 miles, drain the oil and change the filter. Now allow the engine to cool right down-24 hours-then re-torque the bolts. This will have lessened the clearances a fraction, hence the need to re-set the tappet gaps.

 

[jack23247]

Don't go mad with aggressive cleaning, as you may cause more damage than you mean to. Once everything is back together and running properly a great deal of the "muck" will burn off if the car's taken on a few long runs. Remember a car is, in many way like one's body and needs regular exercise; sitting around and only doing small walks (short slow runs, in vehicular terms) aren't good for one's body or one's car. A steady run along a motorway at a steady 50-60 helps "clear the tubes" so will help a lot when you have the chance to go for long run.

You're right. My only concern now is removing the carbon chunks and other debris from the cylinders as I fear they might scratch the liners. I'm planning to use a soft brush and diesel to dissolve the chunks, then use compressed air to trap the residue in a rag.

I have found a shop that will look at the head and refurbish it if possible, but it's going to take a while. In the meantime I want to thank anyone who chimed in and helped so far, I definitely wouldn't have been able to do this on my own!

 

[André4Renaults]

I have found a shop that will look at the head and refurbish it if possible, but it's going to take a while. In the meantime I want to thank anyone who chimed in and helped so far, I definitely wouldn't have been able to do this on my own!

It should take a while, as it's a complex and labour intensive procedure. A company who take their time are doing it properly, as it shouldn't be rushed. Once you have the head back handle it very carefully, placing it upside down, to protect the newly machined surface from any scathes or marks. In the meantime you should buy a new head gasket (unless you've already done so) as you'll need one when you reassemble the engine. [Cliché free post!]

 

[edwin]

Going back to the start of this, I saw a little mayonnaise on the underside of the oil filler cap, none on the dipstick, and so went down to my local trusted garage , with R4 experience here in France. I said how much for a head gasket change, and he said why, and I showed him the car. He said absolutely no problem, it’s condensation, and that’s it. So not to worry or do anything. I also passed the control techniques today as well. Yippee.

 

[jack23247]

Hi everyone! A few updates: I have found a shop and they're refurbishing my head, plus they gave me new bolts and a complete gasket kit. In the meantime I have ordered a Haynes manual and I have acquired both a feeler gauge and a torque wrench. I have not been able to find the Permatex sealant in stock anywhere, the closest thing is Liqui Moly Copper Grease (which seems wrong to me).

I have a question regarding oil: the 4L manual calls for 20W40 or even 20W50, is that right? Will a slightly less dense oil like 15W30 cause any damage?

Also, someone I know suggested I could use Loctite for securing the head bolts that were previously loose. What do you guys think about that? Personally I'd rather not use any.

Thanks in advance, I hope I'll be hitting the road soon!