Team-BHP - What to do if your Engine Overheats on the road

Quote:

Originally Posted by deep_bang (Post 3464647)

Ideally, the car should not lose water or coolant at all, Atleast not over a few days. Are you saying that after a 10 km drive the coolant level in the coolant reservoir is reduced by about 250ml? If that's the case I suspect that there is a leak somewhere in the whole pipeline - either the pipes connecting the coolant reservoir to the radiator, or the radiator itself.

Yes the car loses water. The consumption has reduced now though. Yes the water/coolent reduces around 250 ml after a drive of 15-20 KMs drive. We tried to look for leakages but have not been able to find one. You can see the water spill marks outside the coolent reservoir. And i drove the car around 6 KMs today morning though the car did not show any syptoms of overheating but on opening up the coolent reservoir it was full with the water. That means car is pushing the water out. And my mechanic is suggesting a head gasket change. Any suggestions ?? I am sure i did not find any oil in the coolent reservoir but still I will check again in the morning.

nIk

Nik, The first thing I would like to know is what valve was missing? (Wondering if the thermostat was removed precisely because of this problem). Secondly, you did not indicate whether your radiator fan/fans were working at all. Thirdly, are there any signs of oil in the coolant or vice a versa. (Though you can still have a blown head gasket or cracked head without any cross-contamination)

There are several ways of figuring out whether you have a blown head gasket or not. But before we do that, let's try and figure out what is going on with the system and where the water/coolant is disappearing. I am assuming with all the water that you've been adding to the system there is probably very little coolant left and mostly water. If you could, kindly do the following:

1. With the engine cold, open the radiator cap and examine it to make sure that the spring and seals are functioning properly.

2. Fill the radiator with coolant/water till it is completely full and make sure the reservoir is about three fourths full.

3. Start the engine, engaged the emergency brake, and put the air-conditioning on high. This will help warm up the engine quickly.

4. Once the engine reaches operating temperature, switch off the air conditioner and keep the engine at a steady 3000 RPM.

5. Observe the cooling system under the hood, see if there is excessive pressure in the upper radiator hose, if the radiator fan is cycling normally, if coolant is overflowing into the reservoir, is there any coolant leaking from anywhere onto the road?

6. Also check to see if you're getting any white smoke out of the exhaust.

If you can manage to get the car to overheat we will be able to determine what is going on. So far, from what you have told us, it seems that it is overflowing out the reservoir.

Quote:

Originally Posted by Ray32825 (Post 3464657)

Nik, The first thing I would like to know is what valve was missing? (Wondering if the thermostat was removed precisely because of this problem).

Hi Ray,
It was not the thermostat the mech. Says there is a valve in the elbow and he changed it.

Yes, as the water/coolent is always low even after a few KMs drive the fan starts working as soon as you start the car and turn the AC.

I didn't find any oil in the coolent.

True. I would say there is only 5% coolent left in the system.

I don't think it's the problem with the radiator cap as I don't see any coolent/ water around it. Still I can try to use my Gypsy's radiator cap.

I don't see any leakage at all. We did try this. But in a different way. After a drive of some 10 KMs we let the car cool for some 30 min. Than we opened up the radiator cap and put water in it and turned on the AC. After a few min it started throwing out the water. A 2 feet high stream of water was coming out from it.

6. Also check to see if you're getting any white smoke out of the exhaust.

There is no smoke from exhaust at all.

If you can manage to get the car to overheat we will be able to determine what is going on. So far, from what you have told us, it seems that it is overflowing out the reservoir.

Yes, it is flowing out but I am not able to find the reason of it.

nIk

Nik, some points to check:

1. Check radiator cap. Replace from a known good one and try.

2. Check if the flow to the overflow container is not choked.

3. Get the hoses drained, flush the radiator and refill fresh coolant and water. It can be a case of air bubbles locked in the system or a choked radiator.

4. Check thermostat.

5. Blown head gasket.

These are what can fail commonly in a cooling system and inspecting these points should get your problem fixed. And all cars will lose water level if there is no coolant in the system since water will evaporate due to the engine temperature.

Quote:

Originally Posted by saket77 (Post 3465112)

Hi Saket,

The problem doesn't seem to be with radiator cap as I do not find any water/coolent marks around the cap.

The pipe to the overflow container( I am assuming we are talking about the coolant reservoir) is not chocked.

The mechanic says he has flushed the radiator. How do I confirm as I was not present when it was being done.

How do I check the thermostat.

Blown gasket is what my mechanic is suggesting. He says he will open up the head and will check if it can be done with replacing the gasket and facing the head he says otherwise I will have to replace the head.

nIk

Thanks for a well versatile thread on the overheating. In some areas people use non-distilled water which cause scales in the inner lining of the radiator as well in the water chamber. These calcium deposits cause less heat transfer leading to overheating as well in the long run. If by chance hard water is used (more calcium), it is difficult to remove the calcium lining from the water chamber.

Quote:

Originally Posted by nik0502 (Post 3465135)

Bubbles in the radiator would mean the water is actually boiling, which it should not in a pressurized system, no?
Before opening the head, ask your mechanic to take out the radiator and do a pressure test for leaks.
BTW, is your mechanic an ASC?

Quote:

Originally Posted by mayankk

Hey,

I will try the pressure leak test. My mechanic works for an independent car garage.

Quote:

Originally Posted by mayankk (Post 3465188)

Bubbles in the radiator would mean the water is actually boiling, which it should not in a pressurized system, no?

No, not true, basic fysics:
Increase of pressure will increase boiling point. This is the basic principle behind a closed loop cooling system. As the cooling liquid heats up it expands, thus increasing the pressure and thus boiling temperature. So the system can operate at a higher temperature.

So if you see bubbles it can mean two things:

- There is not sufficient pressure and the boiling point has come down, hence the bubbles.
- There is sufficient pressure and the cooling liquid is actually boiling.

So pressure testing would be a sensible thing. Most cases of bubbles its likely to be lack of pressure.

Jeroen

Quote:

Originally Posted by Jeroen (Post 3465317)

- There is not sufficient pressure and the boiling point has come down, hence the bubbles.

Exactly, If there are bubbles present that means the loop is not 'full' hence presence of air to fill the gaps hence the pressure is not building up.

If the loop was pressurized then the bubbles will not be present.

Anurag.

Quote:

Originally Posted by a4anurag (Post 3465326)

No this not correct. You seem to be under the misapprehension that the cooling liquid will not boil under pressure. This is incorrect, it will boil at a higher temperature.

So you can't say anything perse about the pressure merely by having bubbles or no bubbles. Elementary fysics.

Having said that, in most cases bubbles is likely to mean no pressure. But it's not necessarily the case. In fact if you see bubbles in a closed loop system that holds its pressure there is a very serious problem. Also, it could be due to exhaust gasses being blown into the cooling water.

Seeing bubbles with no pressure is often a simple problem, e.g. a simple leak or more often wonky radiator valve/gap or similar.

Jeroen

Quote:

Originally Posted by nik0502 (Post 3464649)

1. Check you Oil level. If its low, top it off, and check again after a week or so. The level should not go down.

2. In the morning let it idle for 5 mins. then revv hard. Do you see, white or blueish smoke coming from exhaust.

If yes- blueish then gasket needs replacement. If white, piston rings need replacement. In both the cases you will loose oil within a matter of say three days of normal driving.

Now back to your radiator issue.
1. there is a thermostat valve in somewhere in coolant line. tell your mechanic to remove completely. Its needed only for cold areas, like in hills. If you live in plains you dont need it.

2. the radiator and coolant reservoir, if clean green then your mechanic has done the flush honestly.

3. but radiator blockage cannot be checked. easily. there are specialist for it you know.

thanks