[archat68]

I have a Swift D run 67K KM so far. About 20K KM ago on highway the coolant leaked due to a damaged hose pipe. I didn't notice the overheating immediately. Ran about 20KM after the overheating started (assumption). The was still running when I noticed the temperature gauge, Switched off the engine, opened the bonnet, noticed the coolant leak, waited some time and when the temp needle returned to normal zone I had to drive slowly (keeping an eye on the temp gauge) 4-5KM to a service station. The hose pipe was changed there and the car gave no problem after that although it is a bit rough after that incident.

Recently about 10K KM ago while changing the coolant the service centre people informed me the head gasket is probably damaged as I have some oil in the coolant reservoir. They showed me the coolant reservoir cap with some sludge formation. I was advised to hand over the car for head gasket replacement.

Now after 10K KM and about 8 month I'm monitoring the car regularly. There is no performance drop, no white smoke in the exhaust, no issue of engine oil consumption (in fact the oil is almost at the same level compared to the the filled level 6500 KM back), coolant level is also OK.

So, my question is do I need to change the head gasket immediately? Is there any way of physically checking the head gasket?

[Jaggu]

If your coolant and oil are not getting contaminated (mixed) and there are no signs of sludge in either of them, you are ok for now, since the car is otherwise running normal.

[rajeev k]

Let me ask another question. Is there foam in the oil?
If in doubt do an engine compression test.

[archat68]

Originally Posted by archat68

Recently about 10K KM ago while changing the coolant the service centre people informed me the head gasket is probably damaged as I have some oil in the coolant reservoir. They showed me the coolant reservoir cap with some sludge formation.

Originally Posted by Jaggu

If your coolant and oil are not getting contaminated (mixed) and there are no signs of sludge in either of them, you are ok for now, since the car is otherwise running normal.

There is some sludge in the coolant reservoir cap. Except that it is fine.

Originally Posted by rajeev k

Let me ask another question. Is there foam in the oil?
If in doubt do an engine compression test.

No foam in engine oil. Since I don't have much knowledge can a compression test reveal the fact?

[oxyzen]

Oil in coolant reservoir is not as dangerous as coolant in oil sump.

IMO gasket change should be avoided if possible.
Just follow the following steps.

• Do a coolant drain and check for oil (again).
• Do a oil drain and check for coolant. A better option is to completely remove the sump. As coolant being heavier will settle at the bottom of the sump and might not come out from the drain plug.
• And a compression test should reveal the rest.

In OEMs we Do a high pressure leak test, where air at high pressure is provided to the cylinders one by one (Through spark plug / Glow plug port). The leakage of air is monitored in coolant inlet & outlet hose as well as the adjacent cylinder. Now I suppose that is not possible at dealer end so a standard compression pressure test should suffice. However note the compression pressure gauges are highly in accurate. I would suggest you to get it checked from at-least 2 workshops.

[vikram_d]

Originally Posted by oxyzen

Do a oil drain and check for coolant. A better option is to completely remove the sump. As coolant being heavier will settle at the bottom of the sump and might not come out from the drain plug.

Woah. Hold on. If coolant is heavier than oil then the first thing that should flow out of the oil sump drain plug is coolant and not engine oil and this is because the oil sump drain plug is normally positioned at the lowest point of the sump. So by this logic if there is coolant mixed with engine oil and it being heavier has settled at the bottom, then the coolant should flow out first and then engine oil.

[rajeev k]

Originally Posted by archat68

Since I don't have much knowledge can a compression test reveal the fact?

As there is no symptom of a gasket failure as of now, a healthy and normal compression once confirmed can help you leave away all the worry. A gasket failure between the oil drain provisionand water jacket notwithstanding, which is totally ruled out if the coolant is free of oil and the oil is free of the coolant.

[oxyzen]

Originally Posted by vikram_d

the oil sump drain plug is normally positioned at the lowest point of the sump.

Not exactly. Even after complete draining of oil, there is around 100-200 ml volume left in sump (atleast in all petrol engines). So if you have around 50ml of coolant left, you might never know.

[Jaggu]

Guys its not that difficult, if the oil is foamed up OR coolant has floating sludge, then only there is a serious issue. Anyone can check this by opening the coolant tank reservoir when the engine is cold, or by just checking the engine oil consistency using the dip stick, again when the engine is cold.

[archat68]

Thanks guys for replying!!

Engine oil is free from coolant.

I'll get the coolant drained in my presence and check if there is traces of oil. A few month ago I got the coolant drained and the radiator flushed to remove the traces of oil in the radiator. I got it done from a local garage (not MASS). However, I was not present at the time of draining the coolant, so couldn't comment whether there is still oil in the coolant or not. They didn't cleaned the coolant reservoir cap which already had the sludge on it :( . So, I'm not sure if oil is still leaking or not.

Also, the containers used by the service stations are generally dirty with oils and what not. So it would be impossible to check for presence of oil. I'll carry a clean container from home next time.

I was closely monitoring the engine oil level for the last few months and it is almost constant. Isn't the level supposed to drop in case the leak is still there? I drive my car about 80KM almost everyday.

[vikram_d]

Originally Posted by archat68

Thanks guys for replying!!

Engine oil is free from coolant.

I'll get the coolant drained in my presence and check if there is traces of oil. A few month ago I got the coolant drained and the radiator flushed to remove the traces of oil in the radiator. I got it done from a local garage (not MASS). However, I was not present at the time of draining the coolant, so couldn't comment whether there is still oil in the coolant or not. They didn't cleaned the coolant reservoir cap which already had the sludge on it :( . So, I'm not sure if oil is still leaking or not.

Also, the containers used by the service stations are generally dirty with oils and what not. So it would be impossible to check for presence of oil. I'll carry a clean container from home next time.

I was closely monitoring the engine oil level for the last few months and it is almost constant. Isn't the level supposed to drop in case the leak is still there? I drive my car about 80KM almost everyday.

From what you have said, there doesn't seem to be anything wrong with your car. If the oil level is not dropping then you should be ok and this is considering your 80kms/day driving. So stop worrying and enjoy driving.

[SS-Traveller]

Originally Posted by archat68

So, my question is do I need to change the head gasket immediately?

You don't have any major symptoms of head gasket leakage, except for some sludge in the radiator/reservoir cap.

At the time of overheating, some oil may have leaked past the head gasket at one or two points. Once the block cooled down, and with a bit of carbon deposit, the leakage may have stopped.

The gasket seal at the leakage point isn't perfect at the moment, but it is preventing oil & water from mixing, as well as holding up the compression.

If you do not do long-distance/high-speed/high-rev runs with your engine, the likelihood is that the seal will hold for quite a long time. OTOH, the reliability of the engine may not be perfect if you plan to do a long-distance high-speed drive.

Whether you want to change the head gasket will depend on how you plan to use the car. For me, I would assume that my 1500-km run in 20 hours will cause the head gasket leakage to recur at the most inconvenient time - and therefore I would replace the head gasket for the sake of 100% reliability (replacing head gaskets is not a very complicated task, just time-consuming). For you, if your run is confined to within the city and at low rpm, you could choose to continue to use the car as-is, till some symptom (coolant in oil, oil in coolant, poor performance etc.) shows up - keep a close watch anyway. With any luck, symptoms won't come up soon.

[dhanushs]

+1 to what SST said.

IMO, the leak will most probably occur, only when the engine is hot and the rpm is high (enough), as usually normal city runs wont throw up any issues.

If you need perfect reliability, and tension free trips, please do go ahead and change the gasket.

[archat68]

Thanks everybody!!
I think I'll live with it now as there is no major symptoms. I'll keep a close watch on the coolant, engine oil.

[rajeev k]

Originally Posted by SS-Traveller

The gasket seal at the leakage point isn't perfect at the moment, but it is preventing oil & water from mixing, as well as holding up the compression.
I would replace the head gasket for the sake of 100% reliability (replacing head gaskets is not a very complicated task, just time-consuming).

Originally Posted by dhanushs

IMO, the leak will most probably occur, only when the engine is hot and the rpm is high
If you need perfect reliability, and tension free trips, please do go ahead and change the gasket.

Yes, better plan for a head gasket change as it will not cost much and could be completed in a morning-till-evening stay at a garage. Definitely reliability factor is of prime importance for a car. Only thing is the garage should be a reliable one or else he can scare you by saying this this is worn out that is to be changed et al. 67K is definitely not a high mileage and not even a manual de-carbonizing is essential.