XSeries-forum

Hello all,

My expansion tank has tiny pinhole leak in it at the very top.

Has anyone used will JB Plastic weld epoxy to fix it?

It can seal upto 3200psi so I guess it can take the pressure.

Thanks in advance.

Bmw E53 X5 4.6is

Funny this thread coming up as literally just found the expansion tank on my 4.8is has just suddenly cracked. Not sure how but I was just gonna buy a new tank from the dealer tomorrow.

As mine is only losing a tiny bit im thinking for £5 ill give it a whirl 

A few people seem to have done it on other beemers and been successful.

Hopefully someone on here has done it.

[quote="Raj"]
Funny this thread coming up as literally just found the expansion tank on my 4.8is has just suddenly cracked. Not sure how but I was just gonna buy a new tank from the dealer tomorrow.
[/quote]

I tried this on my E39 as I was stranded on m'way no. of years back... although with superglue.

Just couldn't be bothered to be towed away and go through that routine. S'glue didn't work and ended up with 2x5l water tanks that worked well on a 60mile journey home [with couple stops of course] )).

I think that replacement is ~50quid + some antifreeze etc so it should cost more than 80-100 all in. and it is something that can be easily DIYed [for even less].

Hope that helps

The Tank will be Poly Propylene or carbon reinforced plastic, and nothing will stick to either long term.... ever !

The superglue or epoxy fix will be a temporary at best and should not be considered permanent.

So, on the basis your engine is worth more than £50 to you, strongly suggest you get a replacement tank, new or used asap. 

Interesting topic this as recently I have been losing coolant and there seems to be dried coolant (white flakey bits) around the expansion tank. I also noticed when topping up the coolant that there is no pop-up level indicator - or rather nothing pops up when you remove the cap to indicate min / max levels for topping up.
Im no expert but I think all points to a new expansion tank needed......so can anyone give DIY instructions on how to do it ? If its not really straightforward then I will get it done - but I am willing to give it a go !

Ro.

Again emphasizing that the only way to fix the expansion tank is to REPLACE IT.

The coolant is essential, and a lack of it will kill your engine properly . . . . .

Just get another expansion tank and not risk cooking the engine.

By the time you may notice the temperature gauge bending the needle at the hot end . . . it will be too late & a head gasket is cooked.

The X5 engines are fabulously engineered, but they need cooling properly . . . . always.

Mine went last month on the X. Crapped my load when the needle went past the half way. All in all cost me £160.00 to ha e it done from my indi with genuine BMW tank. This included a full antifreeze change.

The bleed valves can fail too- worth keeping the old one as a spare.

I accept the cautionary advice here but it would be interesting to know if such a repair would hold - even temporarily ( as it could be worthwhile having same as part of mobile car first aid kit).

Changing tank and coolant is an easy diy if airlocks are properly bled.

Mine split last week, fitted a genuine one myself aprox £80 for the part .

Easy enough Diy job.

I wouldn't be tempted to glue it as said if you are stranded or it overheats then you have a bigger issue to deal with .

[quote="RoShamBo"]
Interesting topic this as recently I have been losing coolant and there seems to be dried coolant (white flakey bits) around the expansion tank. I also noticed when topping up the coolant that there is no pop-up level indicator - or rather nothing pops up when you remove the cap to indicate min / max levels for topping up.
Im no expert but I think all points to a new expansion tank needed......so can anyone give DIY instructions on how to do it ? If its not really straightforward then I will get it done - but I am willing to give it a go !

Ro.
[/quote]Replaced mine on 4.4 £55 Euro parts leak from base where two moulded spigots are,temp sensor in one a note of caution never fill over max?? Follow levels on indicator can cause 'splitting' probs  :blink:

[quote="stevox5"]
Mine split last week, fitted a genuine one myself aprox £80 for the part .

Easy enough Diy job.

I wouldn't be tempted to glue it as said if you are stranded or it overheats then you have a bigger issue to deal with .
[/quote]

Agreed. I picked up a new tank from Sutton Coldfield for under £70 and got 2 bottles of antifreeze to flush the whole system for £5 too lol.

Although i've ordered the glue, i've read your replies and ordered a new one, only £38.34 from ECP so cant complain really.

I recently fitted a new water cooled alternator which involved draining and adding new coolant and i'm wondering if I have over filled the system slightly, as didn't have a problem before. I followed the automatic pump bleed procedure, but also made sure the level was correct.

Or I wonder if it was because the day I did it the temp was around freezing and car had been sitting on the drive Whilst I did the alternator job, maybe the plastic being 11 years old couldn't handle the freezing then being warmed up, or maybe a combo of the above?