E86 multi incontinence

[axelleveau]

Hi all,

As already discussed in the "What have you done to your car today?" thread, my Zed is leaking from both the washer circuit and cooling circuit but I decided to start a dedicated thread as to not polute the other one. I already had some good avices from [ref]Barty[/ref] and [ref]enuff_zed[/ref] which helped me look in more detail during a quick lunch break today. So here is where I have got to:

1. Main source of liquid clearly is the washer jet as "fresh water" is accumulating in front of the left wheel and I clearly traced the source of the leak. (Water did not freeze in there, I only used fresh water as a temporary solution while looking for the leak instead of wasting washer fluid). It sounds like replacing the jets is neither expensive or difficult so that should be good. I will do a good clean of the system while in there.



2. It was advised I should change the water pump and thermostat while opening the cooling circuit. I can confirm thermostat is dated 12/06 and based on how it looks the water pump probably is the same so I guess I should just go for it? They both are on 103k miles at this point...



Is it also recommended to change the short and big pipe that goes from pump inlet to thermostat outlet? I have seen some pumps come with it as a kit.

3. I am not 100% sure of the source of coolant leak as there still is some wet spots in the area around the expension tank (nothing else in the engine bay shows wet signs and I expect "and don't even want to think" that a head gasket or oil cooler would be more catastrophic. I am almost sure though that it comes from the connection at the bottom of the tank which is the by-pass hose / cold thermostat feed. I do not know if this is where cracks tend to appear but I also red online the o-ring in there tend to give up. We can see coolant seem to have come down along the ribs reinforcing the pipe:



On top of that, that same hose has both retaining clips free so it might have put additional strain on the connection. I will close the clips while doing the bulk of the repairs as it is a pain to access...


I would just like to be 100% sure the leak does not come actually from somethig else nearby and have to flush everything again. It seems like pressure testing kits are expensinve so I might just drive and get the car up to temp again in the hope that heat will help dry the area while pushing more coolant from the leak too.

4. Thanks [ref]enuff_zed[/ref] for advising changing the aux belt while in there.I had a look at it and am happy with how it looks at this stage. I will wait so I do not have to spend a load of cash in one go and as access is easy and not requiring extensive disassembly of other components , I can do it at a later date

 

[enuff_zed]

The expansion tank splits do tend to be invisible when cold, then open up under heat and pressure.
However, when I did the one on the wife's car it turned out to be the O-ring at the bottom where the tank pushes into the housing. That had flattened out and was leaking.
Another thought: is your car an automatic? If so then there is a thermostat assembly that sits inside the bottom of the expansion tank. I think it is to divert coolant to the transmission oil cooler. This gets brittle over time and has a big spring inside.
When I removed the expansion tank I turned away and heard a crack, then part of this thermostat assembly shot past my ear!
I think Stuart (Bigwinn) had the same issue.
So IF it's an auto, buy yourself one of those thermostat assemblies first, or like me you'll be sat around for a couple of days waiting for one to arrive.
I was also forgetting that you have the electric water pump. I have no experience of those, but anecdotal evidence on the forum is that yours (assuming it is the original) has already exceeded the commonly accepted lifespan! I believe it's quite expensive, but many people can advise on where to save money on that item.

 

[axelleveau]

The expansion tank splits do tend to be invisible when cold, then open up under heat and pressure.
However, when I did the one on the wife's car it turned out to be the O-ring at the bottom where the tank pushes into the housing. That had flattened out and was leaking.

Sounds like the o-ring either from the outlet pipe or the "housing support" is common issue then. I guess some driving up to temperature will confirm all that.

Another thought: is your car an automatic? If so then there is a thermostat assembly that sits inside the bottom of the expansion tank. I think it is to divert coolant to the transmission oil cooler. This gets brittle over time and has a big spring inside.
When I removed the expansion tank I turned away and heard a crack, then part of this thermostat assembly shot past my ear!
I think Stuart (Bigwinn) had the same issue.

An auto what? I have to admit that as an engineer who works on cooling systems for both engines and electric vehicles (feel the irony there ) the way they implementd the expension tank and the flexibility to integrate the thermostat for the TOC is pretty nice. If only it was a bit more robust... I am glad I do not have the TOC, an LT circuit for charge air and emachines and a refrigerant system that does heat pump and cools a battery as my days are already filled with that

I was also forgetting that you have the electric water pump. I have no experience of those, but anecdotal evidence on the forum is that yours (assuming it is the original) has already exceeded the commonly accepted lifespan! I believe it's quite expensive, but many people can advise on where to save money on that item.

Looks like Autodoc, Euro Car Parts and all the usual websites sell them. I have seen Pierburg units at around £275, hoping I could get one around 250 with a good sale.

 

[Mr Tidy]

If your car is on its' original water pump at 103K miles it might be worth fitting a new Pierburg water pump as it's a real pain if it dies when you need to get somewhere.

My first Z4 needed one at 60K but my second seemed to be on the original at 91K. My E91 325i needed one at 135K, although that may have been its 2nd one!

Good luck getting it all fixed.