Diagnosing coolant leakage in oil

[jack23247]

Hello everyone,

I am trying to diagnose a rather worrying problem with my engine: after letting the car run for a while, bubbling can be seen in the coolant expansion tank/reservoir when accelerating. After shutting the car down, overnight, the whole contents of the reservoir disappear. I have confirmed that the water is going into the oil, as the oil cap shows the usual water/oil emulsion, and the level of the oil in the pan has definitely increased despite not adding any. There seems to be no oil in the coolant, though, or at least I could see no oily stuff floating in the radiator. The level of the coolant in the radiator does not change.

The engine's always had a tendency to eat some coolant but the bubbling has never been this noticeable until recently, and the level of the oil had never increased before. I have turned the car on probably once or twice since the problem appeared and, sure enough, it smoked terribly for a while. When it stopped smoking, though, it ran fine until parked. I have decided to avoid cranking the car until I can at least drain the oil and flush the sludge out of the engine, but I doubt that alone will solve my problem.

Some information about the history of the vehicle:
- The car had a new head gasket installed in 2017, and the head has been lapped. I've used the car as a daily driver for several years after the replacement of the head gasket with no major issues.
- The car has suffered a problem, as described here, due to a missing support strut: in several occasions, the engine has suffered violent vibrations for limited amounts of time. The bubbling has definitely started several hundred kilometers after the issue with the support strut first presented itself, and it has worsened after the support strut was reinstalled. I'm not sure there's a connection between the two issues but it might be an useful detail to mention.

Any help will be greatly appreciated!

 

[malcolm]

Oil cap can get oil/water emulsion through lack of use. Does the oil on the dipstick have the emulsion? That would indicate a leak between the water system and the engine oil. Worth confirming that before doing anything. Support strut would make no difference to this.

Should you have emulsified oil then there are 2 possible reasons - leak at the top of the liners or leak at the bottom. Leak at the top is more likely if you also have the bubbling in the expansion bottle. Might be the head wasn't torqued for the second time 500 miles after the replacement. If so head off, check flatness, new gasket. Easy and quick to do.

 

[jack23247]

Oil cap can get oil/water emulsion through lack of use. Does the oil on the dipstick have the emulsion? That would indicate a leak between the water system and the engine oil. Worth confirming that before doing anything. Support strut would make no difference to this.

Should you have emulsified oil then there are 2 possible reasons - leak at the top of the liners or leak at the bottom. Leak at the top is more likely if you also have the bubbling in the expansion bottle. Might be the head wasn't torqued for the second time 500 miles after the replacement. If so head off, check flatness, new gasket. Easy and quick to do.

The oil on the dipstick does not seem emulsified (i.e. there are no brown streaks/bubbles), but I'd need to drain it to be 100% sure. There is definitely too much liquid in the oil pan, the dipstick shows a level way above the maximum. It can't be all oil as I'm sure I've not added any since I had the strut reinstalled.

I can confirm that the head has not been torqued after the replacement. I am comfortable with minor repairs but I've never opened up an engine: should I get it done professionally, or is it something I can do myself while learning a thing or two? I don't wanna risk damaging the engine but I'm definitely curious.

 

[malcolm]

It is worth draining some oil. Oil floats on top of water so water should be the first to come out of the drain plug while you try to get the oil to the correct level. That would also be a good clue for what is going on.

Might just be a bad water pump or something

 

[jack23247]

Thanks for your help so far! I'll drain the oil and report back.
Regarding the water pump: good idea, I should be able to take it apart and check it on my own.

 

[angel]

I can confirm that the head has not been torqued after the replacement.

Here is the key to your problem. Almost certainly the head gasket has blown because it settled down as it should - that's why re torquing shortly after a head gasket replacement is imperative.
Probably cylinder head is not warped but it wouldn't do any harm to check it. Head gasket replacement is easy and no special tools needed, apart from a good torque wrench, obviously. As you will not need to mess with valve removal etc, I think it's doable by a mechanically inclined amateur.

 

[jack23247]

It's been a while but I've found some time to work on the car today.

First of all, thanks to everyone who chimed in for your insights: I am trying to decide what to do. I have drained the "oil" and it's back to its proper level, but the amount of coolant in it was rather worrying.

The coolant will still mix with the oil while the car sits still in the garage, so I can't refill the coolant reservoir. The oil is worn out and heavily emulsified, and the car will likely require an oil system flush. I am not even sure whether it's safe to turn the car on in this state, I'm worried about potential engine damage (I hope not because it's been driven already in this state, albeit for a very small distance).

Even if I'm able to get the head off by myself, I might still need professional help in case it needs resurfacing and to torque it properly. I'll disassemble the water pump first, then report back.

 

[André4Renaults]

Clearly your first objective must be to find from where the oil and water are mixing. Having read back over this thread it suggests the cylinder head may be the cause of your problems, so I would tentatively suggest removing the cylinder head and checking by observation of the gasket and by examination of the head itself to determine if this is indeed the cause of your problems. A local engineering company may help by running an engineer's straight edge over the head, to determine if it's been kinked. As has been said already, a decent amateur mechanic should be capable of removing the head, and I'm sure you're aware of the usual warnings as to clamping the cylinder linings in place!

 

[Seabadger]

If you've not over-heated it, the head's probably still true. My personnal opinion here - it may be true that the cleaning up of the surfaces and replacing the gasket is best done by the owner. It's not hard - get the gasket the right way up and do up bolts as instructed. But, it takes a long time to get the surfaces properly clean. The Original Poster's surfaces may not be too bad as the gasket is fairly new. Professional mechanics have to charge a lot of money per hour and don't want to give you a horrendous bill. It might take you all weekend, but your time doesn't matter (in terms of bills). Varnishing boats is another case where this is true.
I have had a gasket blow after engine work where I asked for the cylinder head to be changed for a sportier one I had purchased.. I took it off, spent ages getting everything lovely and clean and put it back as per the instructions and had no further problems.
This is just my opinion based on my experience. I appreciate modern mechanics may have some magic tool that cleans surfaces in seconds, I've just not seen it.

 

[jack23247]

Clearly your first objective must be to find from where the oil and water are mixing.

Right, this is my primary concern. The water pump investigation proved inconclusive as I ran out of time and had to stop after removing the hoses, although I was able to confirm that there seems to be no oil floating in the coolant at all. I must note that I was a bit surprised about the placement of the thermostat!

As has been said already, a decent amateur mechanic should be capable of removing the head, and I'm sure you're aware of the usual warnings as to clamping the cylinder linings in place!

What I'm lacking is the confidence to undertake the work and some of the tools (i.e. I don't have a torque wrench). I have little to no experience working on engines and I'll need all the help I can get! I am definitely unaware of the potential dangers and pitfalls and I must document more before as I don't want to go in unprepared and cause damage: as such, any pointers to discussions, procedures, and possibly good videos showing the procedure would be greatly appreciated. For now I have located a service manual that should have the torque pattern but I'm not sure it's right for my engine.

I have had a gasket blow after engine work where I asked for the cylinder head to be changed for a sportier one I had purchased.. I took it off, spent ages getting everything lovely and clean and put it back as per the instructions and had no further problems.
This is just my opinion based on my experience. I appreciate modern mechanics may have some magic tool that cleans surfaces in seconds, I've just not seen it.

That is definitely reassuring, thanks. I was not implying that special tools are needed, but rather that I lack the confidence and possibly the skills to fix the head on my own. However, one must start somewhere and if I need to break something in order to learn and improve, so be it (as long as I don't mess with the block)!

 

[André4Renaults]

In the words of the Apollo 13 mission "Houston, we have a problem", but they were instructed as to what to do, and they made it, so talking you through what's needed shouldn't be too complicated.....

I'll prepare some pieces and post them in order. Read them, and if you don't understand something, say so. We'll do this stage by stage!

 

[André4Renaults]

First things first: do you feel confident enough to remove the cylinder head? In essence, you do the following:
(Pre-cylinder head removal preparation
1/ Drain the coolant.
2/ Remove the air filter, disconnect the pipes and wires from the carburettor, noting which ones go where! Now remove the carburettor and put it somewhere safe!
3/ Remove the hoses from the water pump on the front of the engine.
4/ Remove the fuel pipe from the fuel pump and block the pipe.
5/ Undo the exhaust manifold to the exhaust pipe manifold. It should hang safely....
6/ Remove and secure the throttle cable and the electrical connections to the water temperature sensor
7/ Remove both fan belts and the dynamo/alternator. The gear linkage needs to be removed as well.

Now the cylinder head removal itself:

1/ Remove the rocker cover. This is the metal cover on the top of the engine, held in place by two screw-on nuts.
2/ Remove the spark plugs.
3/ Loosen the cylinder head bolts in the order shown in the workshop book (there are 12 of them) but loosen them in stages, a turn at a time. Be careful to use a correctly fitting socket. This means loosening no. 1 bolt one turn of 360 degrees, then bolt 2 one turn of 360 degrees, then bolt 3 the same and so on, until you've loosened all the head bolts by one complete turn. Continue loosening the bolts in this manner until you can undo them by hand. Then remove all the bolts.
4/ MAKE SURE THE CAR IS OUT OF GEAR and that the handbrake is on!
5/ The head should now lift off. If it doesn't, g-e-n-t-l-y tap it with a soft hammer (rubber or copper capped) on the spark plug side horizontally. until it moves a little, then lift it clear. Place it carefully on a soft smooth surface, such as a pile of newspapers.
6/ Do NOT, under any circumstances, turn the engine over! Now clamp the cylinder liners in place, by using some big washers (sometimes called "penny" washers) which can be held in place by the cylinder head bolts AND can keep the cylinder liners in place too.

Tackle this slowly and methodically and you'll be O.K!

 

[jack23247]

Firstly: thank you, I greatly appreciate your efforts!

First things first: do you feel confident enough to remove the cylinder head?

I should have no problems going through steps 1-7 of the prep work and up to step 2 of the removal process. I am somewhat concerned about the bolt removal procedure and the cylinder liner clamping but I should be able to do it.

3/ Loosen the cylinder head bolts in the order shown in the workshop book (there are 12 of them) but loosen them in stages, a turn at a time.

Is there a specific workshop manual I should look for, or will any of them do? I currently got the RTA manual (in French, I can somewhat read it) from renault-club.cz. I'll note that my R4 has a "Cléon" engine.

Further questions/clarifications:
1. The car is currently on jackstands, should I take it off before tackling the head disassembly or can I leave it there?
2. How easy is it to turn the engine over accidentally? Should I still be careful after clamping the liners? Are there any precautions I can take to avoid turning it by mistake?

Again, thanks for your time and sorry if my questions sound a bit silly.

 

[André4Renaults]

A workshop manual is essential, particularly if you're new to this! It'll repay its modest price many times over, believe me. If you obtain the Haynes one it covers all Renault 4 cars from 1961 onwards, so ought to cover your car.

As to your specific points:

1/ If the car's on stands you'll need to stretch further to get to the engine. I suppose it all depends on how tall and agile you are! Personally I'd have the car on the floor, but I'm only 172cms tall! While it's "in the air", you might find access to the exhaust manifold to the exhaust down pipe bolts easier to undo though.

2/ It's difficult to turn the engine over, providing you remove the causes! Removal of the ignition key, thereby preventing the starter from being accidentally operated, and ensuring the car's in neutral, to prevent any accidental small movement of the car being transferred via the gearbox to the engine are best.

The reason why this is critical with these engines is because they are "wet liner" engines. The pistons slide up and down in liners, which rest in the engine block and are held there by the cylinder head; once the head is removed, should the pistons be moved there's nothing to prevent the liners moving as well, which would involve a load of extra work in re-installing them! However, once the liners are securely clamped in place by some large washers there's nothing to worry about! Renault produced some specific parts to hold the liners in place, and these are shown in the workshop book, but anything that secures the liners in their place will do the job.

By the way, there's no such thing as a silly question!

 

[jack23247]

1/ If the car's on stands you'll need to stretch further to get to the engine. I suppose it all depends on how tall and agile you are! Personally I'd have the car on the floor, but I'm only 172cms tall! While it's "in the air", you might find access to the exhaust manifold to the exhaust down pipe bolts easier to undo though.

I'm 193, hence why I asked! I'm definitely more comfortable with working on the car while it's sitting a bit higher.

2/ It's difficult to turn the engine over, providing you remove the causes! Removal of the ignition key, thereby preventing the starter from being accidentally operated, and ensuring the car's in neutral, to prevent any accidental small movement of the car being transferred via the gearbox to the engine are best.

That's definitely reassuring! I'll be extra careful. And thanks for the explanation.

I have completed most of the prep work. The car is very easy to work on, there's lots of space and you can maneuver yourself around most of the nuts and bolts with ease. The only difficult thing proved to be dislodging the exhaust pipe manifold from the exhaust pipe itself, as it was stuck and filled with carbon deposits.

I hit a roadblock while removing the tensioner for the lower belt as I can't find neither my 16mm socket nor a spanner, so I'll have to restock and proceed another time. I also need some brake cleaner as the engine bay is caked with oily residues. I took a peek under the rocker cover anyway and I didn't like what I saw at all, I'm gonna need to clean it thoroughly with something (a friend suggested using Diesel fuel) before reassembling the head.

By the way, there's no such thing as a silly question!

I hope I won't be the one to make you reconsider this, then

 

[André4Renaults]

I hit a roadblock while removing the tensioner for the lower belt as I can't find neither my 16mm socket nor a spanner, so I'll have to restock and proceed another time. I also need some brake cleaner as the engine bay is caked with oily residues. I took a peek under the rocker cover anyway and I didn't like what I saw at all, I'm gonna need to clean it thoroughly with something (a friend suggested using Diesel fuel) before reassembling the head.

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.

 

[Seabadger]

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.

 

[André4Renaults]

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.

Yes, definitely a good thing to do while preparing to do the job. I ought to have added it to the list!

 

[jack23247]

Quick reply typed on my phone: the head is off! Bolts #5, #7 and #9 were looser than the rest and cylinder #1 is flooded.

 

[jcarruthers2]

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.