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Radiator Coolant Level

Posted: Thu Aug 29, 2019 9:12 am
by pbar
Usually, when I check the coolant in the rad it is close to the top, just an inch under or so, you could certainly dip your little finger in. I assumed this was normal?

But recently, the last couple of times I've checked (when cold), the level is higher in the rad, right to the brim of the neck, the cap is wet underneath for example.

I have also noticed the expansion tank level has dropped a little.

Would I be right in thinking that I must have a slight leak, and so the coolant from the expansion tank is topping up the lost coolant front the rad which is why the level is so high in the rad?

Thanks.

Re: Radiator Coolant Level

Posted: Thu Aug 29, 2019 9:57 am
by Peter-S
I had exactly this a while ago Paul. Wasn't overheating but expansion bottle would empty and the rad brimmed full. Eventually I traced a small weep from around a hose jubilee clip. Sorted that and issue resolved :)

Re: Radiator Coolant Level

Posted: Thu Aug 29, 2019 10:20 am
by pbar
Great, thank you Peter, appreciate it. I did have a quick fumble to check for a leak but I need to have a proper look now.

Re: Radiator Coolant Level

Posted: Thu Aug 29, 2019 2:44 pm
by stevemarl
Posted in error (i.e. didn`t read the OP properly.) Doh!
Paul,
what Peter said, plus the rad *should* be full to the brim all the time though, because it basically vents any XS water and air to the exp. tank as it heats up: cooling down it draws back water from bottom of exp.tank, there should be nowhere for air to enter the system, if you get me? As long as the cap`s seals/valves are in good condition.

Re: Radiator Coolant Level

Posted: Fri Aug 30, 2019 6:16 am
by pbar
stevemarl wrote:
Thu Aug 29, 2019 2:44 pm
cooling down it draws back water from bottom of exp.tank, there should be nowhere for air to enter the system, if you get me? As long as the cap`s seals/valves are in good condition.
Thanks Steve, Yes, that's sort of what I mentioned. I suspected that if there is a leak the coolant in the rad is replenished by the expansion tank, which is why the level goes down.

The rad was unusually full though, I have never known it to be right to the underside of the cap before. It is normally an inch below.

Re: Radiator Coolant Level

Posted: Wed Sep 04, 2019 1:41 pm
by pbar
Peter-S wrote:
Thu Aug 29, 2019 9:57 am
I had exactly this a while ago Paul. Wasn't overheating but expansion bottle would empty and the rad brimmed full. Eventually I traced a small weep from around a hose jubilee clip. Sorted that and issue resolved :)
Seems it was exactly the same for me too, clip tightened (bottom rad hose), and all back to normal. Thanks again Peter, and Steve.

Re: Radiator Coolant Level

Posted: Wed Sep 04, 2019 6:57 pm
by stevemarl
Great! And thanks for the update!

Re: Radiator Coolant Level

Posted: Thu Sep 05, 2019 6:16 am
by pbar
It's good when something is an easy fix :)

Re: Radiator Coolant Level

Posted: Thu Sep 05, 2019 12:49 pm
by andyd
Peter-S wrote:
Thu Aug 29, 2019 9:57 am
I had exactly this a while ago Paul. Eventually I traced a small weep from around a hose
That's old age for you :lol:
pbar wrote:
Thu Sep 05, 2019 6:16 am
It's good when something is an easy fix :)
Glad all sorted :cool:

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 6:03 am
by pbar
Just an update to this, after a drive last night I noticed a tiny amount of coolant on top of the rad at the cap, seeping I assume from a failing cap. So that's what I'm looking at, at the moment.

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 7:32 am
by andyd
pbar wrote:
Wed Sep 11, 2019 6:03 am
Just an update to this, after a drive last night I noticed a tiny amount of coolant on top of the rad at the cap, seeping I assume from a failing cap. So that's what I'm looking at, at the moment.
Sounds like that could be the issue Paul.

Just get a new one :)

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 7:36 am
by pbar
andyd wrote:
Wed Sep 11, 2019 7:32 am

Just get a new one :)
Having just looked at prices, and surprised how cheap they are, then yes I think I shall most likely take your advice Andy. Isn't it great that so many parts are still being produced for our 30 odd year old cars.

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 8:43 am
by stevemarl
stevemarl wrote:
Thu Aug 29, 2019 2:44 pm
there should be nowhere for air to enter the system, if you get me? As long as the cap`s seals/valves are in good condition
That could also explain why you were getting that `air gap` in the top of the rad. Make sure the one you get is identical to the one you remove, as it`s not just a pressure release type, it has 2 seals,one to seal the entire rad, the other `normal` one which allows expansion into the overflow tank (some, without expansion tank just have the latter, XS water is simply expelled onto the road & the shrinkage on cooling draws some air into top of rad.)

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 9:09 am
by pbar
Thanks Steve, it wasn't so much that there was an air gap previously, it's just that now the rad/cap level is too high/overflowing due to the poor cap I think. Therefore the coolant is working past the seal(s) and the cap is soaking. It was never like that previously.

New cap, tight seal, all back to normal, is what I'm hoping :)

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 9:53 am
by andyd
pbar wrote:
Wed Sep 11, 2019 7:36 am
andyd wrote:
Wed Sep 11, 2019 7:32 am

Just get a new one :)
Having just looked at prices, and surprised how cheap they are, then yes I think I shall most likely take your advice Andy. Isn't it great that so many parts are still being produced for our 30 odd year old cars.
:agree:
Many parts are still available from motor factors so you don't need a specialist all the time.

It's these small items that could keep our cars off the road should they become hard to source!

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 11:10 am
by Caprigear
You probably don't always need Specialists but there'll come a time when you won't have them anymore and unless you actually know what you require then the general factors will be no use at all.
Just a thought.

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 12:04 pm
by andyd
Caprigear wrote:
Wed Sep 11, 2019 11:10 am
You probably don't always need Specialists but there'll come a time when you won't have them anymore and unless you actually know what you require then the general factors will be no use at all.
Just a thought.
:agree: Martin.
I like to buy from you as I know it's the correct item and if you use it then it's good enough for me :)

Your advice is invaluable too, especially the seat question, that worked a treat :cool:

Ebay sellers often don't care if it's the right part as long as you buy it, and Motor Factors often only know what's on their computer screen.

:cheers:

Re: Radiator Coolant Level

Posted: Wed Sep 11, 2019 4:19 pm
by Andrew 2.8i
andyd wrote:
Wed Sep 11, 2019 12:04 pm
and Motor Factors often only know what's on their computer screen.
The 88 degree thermostat that motor factors will supply is a good example of that.

Andrew.

Re: Radiator Coolant Level

Posted: Fri Sep 13, 2019 6:02 am
by pbar
In the interim, as I have a couple of other things to contend with, until I buy a new radiator cap, I have turned the existing one round by 180 degrees, this has fixed it for now. Sounds daft but things get 'used' to being a certain way after years, and changing them in such a way makes it new again in part, and has created the seal, as Steve has mentioned above.

Just to conclude this, the issue I had causing the problem was as Peter had previously had, hose clip needing tightening. I also had the issue of the non sealing cap which happened at a similar time.

So, that's that. Thanks for all the replies.