Expansion bottle dip stick.

[Sgr74]

I’m going away with the wife this weekend and was just checking things over. When I opened the water bottle, the dipstick was level with the top. I gave it a little prod because I just thought it had got a bit stuck, but it didn’t bounce back up. So I popped a bit of water in there expecting it to raise a bit. It didn’t. I can’t even grab it with a couple of knives to pull it out. Is there a pressure blow off on the cap if there is too much water in there.

 

[Ewazix]

The float activates the low level sensor, but hey have a habit of sticking or even disintegrating. The float and sensors come with the tank, the tanks are famous for micro splits, leaks and causing potentially disastrous overheating/head gasket issues (and probably the only cause of major M54 engine failure).

Given all the above a new expansion tank is the precautionary way forward, in the meantime it needs to be topped up and monitored closely, checking for micro-leaks. I believe that there is a 2 bar pressure relief in the system so overfilling will normally vent, but allowing it to do so will obviously push the tank pressure to max, which isn't ideal if it's suspect so I'd try and remove a little coolant.

 

[Sgr74]

The float activates the low level sensor, but hey have a habit of sticking or even disintegrating. The float and sensors come with the tank, the tanks are famous for micro splits, leaks and causing potentially disastrous overheating/head gasket issues (and probably the only cause of major M54 engine failure).

Given all the above a new expansion tank is the precautionary way forward, in the meantime it needs to be topped up and monitored closely, checking for micro-leaks. I believe that there is a 2 bar pressure relief in the system so overfilling will normally vent, but allowing it to do so will obviously push the tank pressure to max, which isn't ideal if it's suspect so I'd try and remove a little coolant.

It was a new tank last year so should be fine. I’ve managed to free the dip stick. It’s floating and doesn’t seem to require too much pressure to move it. I think because it’s a float you would feel slightly more resistance if it was too full. I’m sure it’ll be fine.
Thanks for the reply.

 

[Ewazix]

The float activates the low level sensor, but hey have a habit of sticking or even disintegrating. The float and sensors come with the tank, the tanks are famous for micro splits, leaks and causing potentially disastrous overheating/head gasket issues (and probably the only cause of major M54 engine failure).


Given all the above a new expansion tank is the precautionary way forward, in the meantime it needs to be topped up and monitored closely, checking for micro-leaks. I believe that there is a 2 bar pressure relief in the system so overfilling will normally vent, but allowing it to do so will obviously push the tank pressure to max, which isn't ideal if it's suspect so I'd try and remove a little coolant.

It was a new tank last year so should be fine. I’ve managed to free the dip stick. It’s floating and doesn’t seem to require too much pressure to move it. I think because it’s a float you would feel slightly more resistance if it was too full. I’m sure it’ll be fine.
Thanks for the reply.

A new tank is very reassuring, it sounds like it was just the float stuck then. Enjoy the weekend

 

[Smartbear]

The float activates the low level sensor, but hey have a habit of sticking or even disintegrating. The float and sensors come with the tank, the tanks are famous for micro splits, leaks and causing potentially disastrous overheating/head gasket issues (and probably the only cause of major M54 engine failure).

Given all the above a new expansion tank is the precautionary way forward, in the meantime it needs to be topped up and monitored closely, checking for micro-leaks. I believe that there is a 2 bar pressure relief in the system so overfilling will normally vent, but allowing it to do so will obviously push the tank pressure to max, which isn't ideal if it's suspect so I'd try and remove a little coolant.

I think swallowing bits of broken disa valve has a similar effect on the engine
Rob

 

[Ewazix]

The float activates the low level sensor, but hey have a habit of sticking or even disintegrating. The float and sensors come with the tank, the tanks are famous for micro splits, leaks and causing potentially disastrous overheating/head gasket issues (and probably the only cause of major M54 engine failure).


Given all the above a new expansion tank is the precautionary way forward, in the meantime it needs to be topped up and monitored closely, checking for micro-leaks. I believe that there is a 2 bar pressure relief in the system so overfilling will normally vent, but allowing it to do so will obviously push the tank pressure to max, which isn't ideal if it's suspect so I'd try and remove a little coolant.

I think swallowing bits of broken disa valve has a similar effect on the engine
Rob

I guess so, my point was that it isn't worth living with a suspect expansion tank because of the disproportionate damage that can be caused to an otherwise bullet-proof engine.

As a matter of (off topic) interest, in my decade of following all things M54 I've read about a handful of members engines cooking due to leaky expansions, but don't recall any first hand accounts of a member's engine being trashed by the much-feared disa pin? But I accept it's a risk and keep it on the watch list