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Discussion Starter #1
Hello everybody,
I have a Megane 1.5dCI from 2004 that I bought a year ago and this weekend I had a problem with its coolant.
The coolant was changed by me as soon as I got the car, actually all fluids and filters of the car, and the coolant system always worked very fine (no leaks, good heat in the heater, stable temperature, no coolant consupmtion) but at the saturday I drove the car around 20Kms, no smoke nor noises everything ok, parked the car and went do my business. When I returned I notice a small puddle (100ml maybe) of coolant near my front right well and I opened the bonet and the reservoir was empty! I looked around and no signs of coolant anywhere and I had checked the coolant and oil before living my home (I do it every saturday morning). Well, I bought 5 liters of distilled water top up with maybe 2 liters or a little more, checked for air in the system and went home very calmly, as was already night and I had the correct coolant in my house.
Sunday morning came, I got to the car I it had the reservoir complety full and was even leaking through the cap, so I got a 100ml syringe and removed enough coolant to lower it to the max mark, opened the bleeding valves at the thermostat housing and heater hose and turned on the engine. After 10 seconds, the valve at the thermostat housing starts to spils out smoke and bursts of coolant and the liquid at the reservoir is vanished so I top up again, with coolant this time, and suddenly the liquid level starts to rise again until it overflows, in the meantime, smoke keeps coming out of the first bleeding valve and nothing happens at the second one (heater hose), no water nor air/smoke. So I turned off the engine, closed the valves and put back the reservoir cap and here I am.
What can be going on? I had never seen something like that.
I'm sending below a picture of my engine bay.
A = it's a hose
B = the reservoir cap
C = bleeding valve at the thermostat housing
D = bleeding valve at the heater hose

182299


Cheers,
Wesley
 

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Grand Scenic 1.6 2007
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I suspect you may have a large leak. If it's on the right side the usual suspects are the water pump or the return hose from the radiator. Did you open this hose when you changed the coolant?
Fill the system with water and bleed out the air with the motor off. Then go looking for that leak.
The 'smoke' may just be coolant vapour.
 

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Discussion Starter #3
I suspect you may have a large leak. If it's on the right side the usual suspects are the water pump or the return hose from the radiator. Did you open this hose when you changed the coolant?
Fill the system with water and bleed out the air with the motor off. Then go looking for that leak.
The 'smoke' may just be coolant vapour.
Hi Brendan, thanks for your reply.

Well, I did as you said, I filled the system and bled the air. The heater hose had a tiny blockage at the bleeding valve so I stuck a fine wire in it and got out the blockage and got coolant in the valve. Good!
So still without the reservoir cap and both bleeding valves opened I pressed all the hoses to get all air out of the system, and I closed the valves. I got underneath the car looking for signs of leak and I didn't find any, radiator is fine, no signs of leak at the water pump, checked all the hoses and everything is okay, checked the footwells (could be the heater matrix) and both were dry.
So, no leaks. The engine was stone cold and I turned the engine on. A few seconds after, the coolant level at the reservoir quickly starts to raises. I opened the valve at thermostats housing and there was no coolant, only smoke actual gray smoke.
After a few seconds opened, the coolant level starts to lower and I got coolant at the valve so I closed it. Coolant starts to raises again so I opened the valve again and more smoke came out. I repeated the same cycle for like a minute or two, so I took of the engine oil cap to see if there was any sign of coolant there and I left it open.
After that, I closed the valve and turned off the engine and in this moment I could hear a squishy sound coming out of the valve cover, as like some rushes in our out of it.

Well, I tried again, filled the system, bled the air, looked for leaks and nothing. Started the engine and the cycles repeats... coolant raising, opened the bleeding valve, smoke came out and after I little while coolant, closed the valve, the coolant raises and so on.

Whatever is happening is a creating a great pressure in the cooling system. Look at this picture:
There is coolant splashed in the underbonnet.

Could be the head gasket?

Thanks in advance.
Wesley

182313
 

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Discussion Starter #5
Thanks Brenden!
Well, I will search where I can find one to buy, they aren't much common where in Portugal.

I will keep this thread up-to-date if it is really the gasket or not.

Cheers,
Wesley.
 

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Hello everybody,
I have a Megane 1.5dCI from 2004 that I bought a year ago and this weekend I had a problem with its coolant.
The coolant was changed by me as soon as I got the car, actually all fluids and filters of the car, and the coolant system always worked very fine (no leaks, good heat in the heater, stable temperature, no coolant consupmtion) but at the saturday I drove the car around 20Kms, no smoke nor noises everything ok, parked the car and went do my business. When I returned I notice a small puddle (100ml maybe) of coolant near my front right well and I opened the bonet and the reservoir was empty! I looked around and no signs of coolant anywhere and I had checked the coolant and oil before living my home (I do it every saturday morning). Well, I bought 5 liters of distilled water top up with maybe 2 liters or a little more, checked for air in the system and went home very calmly, as was already night and I had the correct coolant in my house.
Sunday morning came, I got to the car I it had the reservoir complety full and was even leaking through the cap, so I got a 100ml syringe and removed enough coolant to lower it to the max mark, opened the bleeding valves at the thermostat housing and heater hose and turned on the engine. After 10 seconds, the valve at the thermostat housing starts to spils out smoke and bursts of coolant and the liquid at the reservoir is vanished so I top up again, with coolant this time, and suddenly the liquid level starts to rise again until it overflows, in the meantime, smoke keeps coming out of the first bleeding valve and nothing happens at the second one (heater hose), no water nor air/smoke. So I turned off the engine, closed the valves and put back the reservoir cap and here I am.
What can be going on? I had never seen something like that.
I'm sending below a picture of my engine bay.
A = it's a hose
B = the reservoir cap
C = bleeding valve at the thermostat housing
D = bleeding valve at the heater hose

View attachment 182299

Cheers,
Wesley
When was the water pump and timing belt last changed?

The water pumps on the older Renaults have a plasitic impeler that fails/detaches from the internal bearing and as such, stops/impedes the flow of cooolant around the engine. This in turn can cause back pressure in the water resevoir and it bubbles over. Also, the heater will blow hot and cold when dr8ving. The higher the revs, the warmer the air and vice versa.

Renault recognised the pump issue a while back and now the new water pumps have a metal impeler that doesnt fail very often.

Before getting a very expensive HG replacement done, get the water pump tested to see if it has failed as it will possibly save you a lot of money.

Hope this helps
 

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Discussion Starter #9
Thank you for your tip! Really great prices and variety of products.



When was the water pump and timing belt last changed?

The water pumps on the older Renaults have a plasitic impeler that fails/detaches from the internal bearing and as such, stops/impedes the flow of cooolant around the engine. This in turn can cause back pressure in the water resevoir and it bubbles over. Also, the heater will blow hot and cold when dr8ving. The higher the revs, the warmer the air and vice versa.

Renault recognised the pump issue a while back and now the new water pumps have a metal impeler that doesnt fail very often.

Before getting a very expensive HG replacement done, get the water pump tested to see if it has failed as it will possibly save you a lot of money.

Hope this helps
The water pump and timing belt was changed in December 2015. I really appreciate your tip, I will look into it.



HI

you can get 'sniff test kits' on Amazon. But as suggested test the thermostat and water pump first.

Al
Thanks, I was hoping to find it around to be more fast, but I couldn't. I will have to order it from the Amazon and wait a little bit.
 

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Captur 2017 1.5DCi EDC
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Thank you for your tip! Really great prices and variety of products.
Some prices are good. Some are expensive compared with Norauto.pt
For critical parts make sure you buy a reputable brand. And as others have said, make 100% sure the problem is the head gasket before replacing it. e.g. gas in the coolant; water in the engine oil; loss of compression; crankcase overpressure; confirm that you have one or more of these.
 

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Discussion Starter #11
Hello everyone,

I'm sorry if a disappeared for a while, a lot of stuff going on at the same time (COVID, car, licenses, house, etc...).
Well, I bought the sniff test and it tested positive for combustion gases and I also asked a mechanical to take a look at the car and it's indeed the head gasket. Actually, this gasket also failed oil to cilinder too, as now the engine smokes and a lot.

We aren't going to fix the car, as it already have 310.000Kms on the clock and two injectors started to fail as well, and the clutch need to be replaced and it's almost time to change the timing belt (5 years), so we are going to say goodbye to her.

Thanks for everyone's help.
Cheers,
Wesley
 
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