Technical Water pressure

[Andycabs]

I asked this in the tail end of another thread but I think it was lost in the trees.
I have a water leak from somewhere back of the engine, yet to be identified..new water pump so it's not that. It loses half a litre per day.

However, leaving the water filler cap "loose" and not allowing pressure to build there is no water loss whatever.

I am fairly happy to do this until such time as the leak can be found/repaired

BUT...I am concerned that running without water pressure may cause a problem in areas I am unaware....one thing that went through my mind is the oil cooler used on some engines,,,consists of a thin membrane between water and oil...prolonged high pressure on one side only "might" cause problems? Beyond this I cannot think of anything else that would prevent the normal day working of the engine till I can have it sorted.

Comments welcome Guys n Girls on anything I have not thought of that may be detrimental to running my engine temporarily like this???Ahhhh

 

[bigdong]

Running without pressure in the cooling system will lead to all sorts of problems as it will reduce the circulation and in some areas have no circulation. Result will be head gaskit or could even result in cracking the block. At the back of the engine there are not a lot of choices for a leak, most likely to be one of the pipes feeding the heater matrix.

 

[Andycabs]

Thanks BD...had thought that the water pump ensured circulation everywhere, if the pressure plays a part too then its panic stations to get it fixed now, and keep the cap on and refill when the red light shows.Ahhhh

 

[Zog]

Running without pressure in the cooling system will lead to all sorts of problems as it will reduce the circulation and in some areas have no circulation.

Isn't the point of a pressurised cooling system that it enables it to run at a higher temperature than "boiling", and that running without a lid on simply means that quite a lot of water will be boiled off?

 

[Andycabs]

At the back of the engine there are not a lot of choices for a leak, most likely to be one of the pipes feeding the heater matrix.

If it is one of these pipes leaking...how straightforward is it to repair? Does the engine have to come out or the dashboard/front of cabin dismantled...after spending over a grand so far to sort this I am Ahhhh in me boots!

 

[bigdong]

To a certain degree you are correct zog, but the cooling system of the engine contains many smaller channels and without pressure the water will allways follow the easy route so proper circulation can not be achieved.

 

[bigdong]

Andy, If it is one of those pipes and the leak is under the bonnet then it should be just a case of a rubber hose and a couple of hose clips. As we are all aware access to the back of the engine is not easy on these vehicles but we usually find a way, often going up from underneath. This pipes are just a suggestion going by the description of the leak you gave. There are not a lot of options if it is down the back of the engine and this would be the most likely.

 

[Andycabs]

Starter motor needed replacing just before some of this....hottest day of the year after; and my engine management light came on (no other warning light) while engine very hot-just over the 90 (normally hovers just above 70)-I assumed then one the air filter pipes not fully seated-unlikly to be MAF since new quite recent. then light went out after a while. Now BD has mentioned about running round without water pressure causing poroblems has me thinking, (ouch!) might this have brought the EML on???. The ELM 327 I bought cheap on fleabay just tells me there is a DFC-but not what it is!

 

[bigdong]

The water pressure is not likely to bring on the EML. As I allways say, try telling your scanner it's reading a peugeot expert, that normaly gives more reliable results.

 

[Andycabs]

No, I was not thinking that the pressure directly brought on the EML-more that the higher temperatures developed in the absence of any pressure, these higher temps causing advanced fuel evaporation and other nashty ittle gremlins. Mine has always run at indicated 72 degrees, it climbs if sat in traffic but never over 90 degrees. I think I have heard some say "normal" should be 90?

I have been using an ELM327 bought off ebay to try and find this fault code and see what is causing the problems. Using program software "ScanTool v1.13" I can only see limited sensor data. It does tell me there is 1 EML code but will not say what it is???

 

[Andycabs]

Andy, If it is one of those pipes and the leak is under the bonnet then it should be just a case of a rubber hose and a couple of hose clips. As we are all aware access to the back of the engine is not easy on these vehicles but we usually find a way, often going up from underneath. This pipes are just a suggestion going by the description of the leak you gave. There are not a lot of options if it is down the back of the engine and this would be the most likely.

Took a good look tonight...no leaks found in rubber pipes I can reach...but its a mystery to me whats behind the cylinder head/injectors...where do the hoses for cabin heater matrix come out in the engine compartment? Is there one of those pressure plug thingys in the murky depths behind, I too ruddy large and old to start crawling under...no doubt this will come...scratching my head so much over this I shall start looking like Kate's other half or one of her puppies!

 

[r masters]

can u not do a test on water pipes to see if they r leaking

 

[Andycabs]

can u not do a test on water pipes to see if they r leaking

Still waiting my mate to borrow a pressure tester...live in hope all will be revealed when we gun that up!

 

[Andycabs]

Still awaiting my mate with the pressure tester...But couple of observations by main dealer techie...thought the Rubber hose going across the top/back of the engine looked as if it may have had a leak where it enters the engine block. He also said they use a silicone gasket on the bare metal water pump flange...seems too many end up losing water here. Will keep you posted.

 

[bigdong]

Still awaiting my mate with the pressure tester...But couple of observations by main dealer techie...thought the Rubber hose going across the top/back of the engine looked as if it may have had a leak where it enters the engine block. He also said they use a silicone gasket on the bare metal water pump flange...seems too many end up losing water here. Will keep you posted.

That would be the hose feeding the heater matrix. As for the water pump, that is why they allways get replaced at same time as timeing belt, THEY LEAK. common problem.

 

[mbev51]

hi
make sure its not the new water pump thats leaking.

 

[Andycabs]

This will be the 3rd water pump within12 months, if this turns out to be leaking I shall book into the funny farm!:bang:

 

[bigdong]

This will be the 3rd water pump within12 months, if this turns out to be leaking I shall book into the funny farm!:bang:

Usually last around 60k miles between leaking & replacing

 

[Andycabs]

:worship::worship::worship::slayer::slayer::slayer: DONE IT!!!

Heater hose that goes from bottom of coolant overflow tank, back behind engine and along to Cam belt/water pump side then down through a metal heat protector sleeve to connect with rear of engine block. Slap bang in the middle of this sleeve was a pin prick hole in the heater hose...when under pressure it was squirting out like a needle, running down the inside of the sleeve and onto the cam-belt/water pump housing. Hence why the water pump has taken the blame and over the past 6 months has cost me plenty in garages for new cam-belts and water pumps!!! I do not know whether to laugh or cry? But its certainly another mystery solved! But wondering how a neat pin hole appeared in that hose hidden inside that protective sleeve???:slayer::slayer::slayer::slayer::slayer:

 

[Zog]

DONE IT!!!

Heater hose that goes from bottom of coolant overflow tank, back behind engine and along to Cam belt/water pump side then down through a metal heat protector sleeve to connect with rear of engine block. Slap bang in the middle of this sleeve was a pin prick hole in the heater hose...when under pressure it was squirting out like a needle, running down the inside of the sleeve and onto the cam-belt/water pump housing.

That's very good, well done!

How did you find it?

Thanks for posting the result!