Overheating... again

[leeorglory]

Well that was short lived... so far I’ve replaced the radiator and fan and this morning on my way to work the car said it was over heating again but this time no steam coming from the engine bay. Given that almost everything else has been replaced I’m assuming this must be down the a knackered impeller on the water pump or a knackered thermostat? But I wanted to come on here and see if anyone had any other suggestions before I buy the parts today. 

Thanks in advance

[Bimmer Owners' Club]

Did you not say that the radiator tank was slightly cracked?

If so, this is definitely where air can enter, you lose the increased boiling point and 'hey presto'

Also, check the condition or replace the pressure cap as this can cause the same problems.

[leeorglory]

Sorry, I forgot to mention that I replaced the cracked radiator at the weekend. So no more crack. The pressure cap being the one you take off to top the coolant up? 

[leeorglory]

So I've finally been recovered back to my house and the guy said it could be a number of things when he was checking the car over he said that the heaters inside the car were never getting hot. I'd never noticed this as I've had the air con on pretty much all the time since getting it as it's been too warm for the heaters.

He thinks it could be either the heater matrix is blocked or broken, the thermostat is knackered or ... dun dun durrr the head gasket.

He did also say that it could be that I might not have properly bled it yesterday when I changed the rad, so with this in mind besides the one on top of the radiator are there any other bleed crews in the system on these cars?

Thoughts?

[Greydog]

First question Lee is it manual or auto ? If its auto then there is a thermostat located at the bottom of the rad under the expansion bottle plus the thermostat in the water pump.

If its head gasket a sniff test at most garages will find out quickly. For your cabin heater you will have an auxiliary water pump in the system trace the pipes from the bulkhead and you will find it not unknown for them to clog or burn out, put your hand on it and get someone to turn on the ignition you should feel it running if not very little heat in the cabin.

Fingers crossed the sniff test is clear

[leeorglory]

Thanks @Greydog

It's a manual car, I'll definitely speak to the garage at the end of my road and ask them if they can test it for me.

I'll also look at tracing those pipes from the bulkhead.

[leeorglory]

Well I've managed to get a sniff test done and thankfully its all clear so not the head gasket at this stage which is a weight off my mind.

 

[Bimmer Owners' Club]

That's good news about the Head Gasket at least but still sounds like air in the system.

If you buy a cheap infra-red temperature gun you can measure the cool spots in the cooling system....hoses, head, etc which tells you where there may be trapped air

[leeorglory]

Yeah I agree there Trevor, but since they're not too expensive I've decided I'm going to replace the thermostat and water pump just to be safe.

 

Out of interest when bleeding the cooling system on a BMW whats the best way to do it? I know the bleed screw is on the rad but I've seen a couple of videos where they say you should have the front of the car jacked up??

[Bimmer Owners' Club]

There should also be a bleed screw just on top of the thermostat area on the engine if I remember right....a small bolt which you (carefully) loosen and it should bleed out any air through that.

[leeorglory]

Thanks Trevor, I'll make sure I find any loosen that one too,

[Greydog]

Good news on the sniff test (your wallet will like that result)

Don't forget the auxiliary water pump Lee if it is running it will help self bleed the system and save a lot of grief. 

With the X5's if it is sticking or not running the job is a whats the word beeeeech, also no heat to the feet. It performs the same function for your car I believe. 

 

[leeorglory]

I feel I finally got to the bottom of this over the weekend.

thankfully @Greydog the auxilliary water pump is fine :)

So it seems that when you buy radiators from Euro Car parts even though you have to put in your registration number it  still shows you two options which both have the same image but are actually completely different, and me trying to keep the cost down decided to opt for the cheaper one, which turned out to be much smaller than the radiator that was previously in there. So I bought another radiator this time the correct size. I also noticed that when I was trying to bleed the system and squeezing the pipe on the cold side I could hear the radiator cap sounding  like it was breathing, since this was the only place I could find any air still getting into the system I bought a new cap from ECP and now it is all running fine :) I took it for a long run yesterday and used it to get into work this morning and it feels so much better. :) 

[Bimmer Owners' Club]

On 10/2/2017 at 9:13 AM, Trevor said:

Did you not say that the radiator tank was slightly cracked?

If so, this is definitely where air can enter, you lose the increased boiling point and 'hey presto'

Also, check the condition or replace the pressure cap as this can cause the same problems.

 

Glad you got it sorted....did happen to mention in my first post reply to replace the pressure cap, but at least it's running good now.

[Greydog]

That's a great outcome Lee, not the cheapest but certainly not the most expensive either. Now you can enjoy your Beemer.

I use www.realoem.com for part numbers then look for the best price for the part I need online. Just put in the last 7 digits of your Vin and hit search.

That way I cut out a lot of guess work

Good luck in the future

[leeorglory]

5 hours ago, Trevor said:

Glad you got it sorted....did happen to mention in my first post reply to replace the pressure cap, but at least it's running good now.

You did, but when I initially checked it over it looked fine, I guess looks can be deceiving.

29 minutes ago, Greydog said:

That's a great outcome Lee, not the cheapest but certainly not the most expensive either. Now you can enjoy your Beemer.

I use www.realoem.com for part numbers then look for the best price for the part I need online. Just put in the last 7 digits of your Vin and hit search.

That way I cut out a lot of guess work

Good luck in the future

Thanks @Greydog I'll defintiely give that a look :)