Coolant System Making Weird Noises

[Marty V8]

Hi,

I am now running in my Griff after rebuilding the engine. Ive now got about 150 miles on it since the rebuild and am coming up against an odd symptom in the cooling system. It ocasionally makes what I can only describe as a 'clacking' noise from the pipework between the thermostat housing and the swirl pot. There seems to be no logic as to when this occurs, it has happened at the start of a journey, and also well into a journey. It doesnt do it when the car is idling and just building up temperature.

I think it might be either an air lock or the coolant bubbling/boiling in the pipework. However, the temperature stays between 70 and 80 degrees whilst the car is moving and doesnt go above 90 when standing. the fans switch in and out okay and everything seems to work as it should, but I cant get rid of this one symptom.

To minimise the probability of the system boiling I've been changing stats and am now on the third thermostat in a week, the latest being a big bore 74 degree Wahler stat complee with jiggle pin (the pin is fitted at the top). Ive also checked this and the other stats Ive had in the car in a pan of hot water and they all work and the Wahler one currently fitted opens nicely at its quoted temperature.

So moving on to the possibility of an airlock and I'm running out of things to try in order to eradicate air locks including the following:

1. I cant physically get any more water in via the swirl pot. I have topped it up and up during a number of heat/cool cycles and it now refuses to take any more. this has all been done with the expansion tank top securely closed. Ive also filled the expansion tank to about quarter full, just in case the coolant system needs to suck any back during cool down.
The expansion tank never used to like to run much more than quarter full before the rebuild.

2. Ive had the car jacked up to try to move air whilst going through a couple of heat cycles.

3. Its been on a couple of 50mile plus runs just to try to move any air in the system.

4. The heater has been bled of air and is working well. I havent been running the car on a journey with the heater open on a journey though as I didnt want to melt.

5. The hose clips on the silicon heater hoses are as tight as I dare tighten them.

6. I have bled all the air from the manifold using what used to be the short rubber hose with the bolt in the end of it (very high tech).

7. Bled radiator from bleed in top offside of rad. Rad itself is only 2-3 years old and flows well.

As Ive more or less run out of ideas on how to get rid of this, I would be grateful for any assitance/advice.

Thanks.

Regards

Marty

Edited by Marty V8 on Sunday 24th July 18:54

[TVR Beaver]

Strange one.. you've not metioned the rad bleed point but I'll assume you've do this (top corner of the rad)...
I had air in my heater for aged... In the end I took the pipes off as high as I could (so bulk head area) and stuck a hose pipe down it... that worked
No problems since...

Not sure if you could get the pipes wrong anywhere.. don't think so?...

have you tried it without the stat?.. does it still do it?...

Are you driving the pump the right way (have seen this before on the serp engines) where the belt is on wrong?

Is the feed to the top up bottle blocked or squashed?

Other than that...

[Marty V8]

TVR Beaver said:

Strange one.. you've not metioned the rad bleed point but I'll assume you've do this (top corner of the rad)...
I had air in my heater for aged... In the end I took the pipes off as high as I could (so bulk head area) and stuck a hose pipe down it... that worked
No problems since...

Not sure if you could get the pipes wrong anywhere.. don't think so?...

have you tried it without the stat?.. does it still do it?...

Are you driving the pump the right way (have seen this before on the serp engines) where the belt is on wrong?

Is the feed to the top up bottle blocked or squashed?

Other than that...

Hi,

I had just edited my original post to say that I had bled the rad. You must have posted at the same time. Great minds and all that...

I might try the hosepipe trick if I cant resolve this, however both heather pipes in the engine bay get very hot, as does the pipework inside the cockpit in the passenger footwell when the heater valve is opened.

Dont think Ive got any pipes mixed up. The only possiblity that I can think of is that Ive reversed the pipework to/from the heater box in the cockpit, but I dont think so, and would it make a difference even if it was?


Ive not tried it without the stat TBH. Its something to think of if all else fails. However it didnt use to do this pre rebuild and the stat now fitted is a lower opening temp than the one I took out of it

Pump is being driven the right way...isnt it? Photo below shows how Ive got it looped round the pulleys



I'll check the hose to the expansion tank as this does pass though a small gap between ARB and body work.

Thanks for the reply.

[FerrariBoy101]

all looks ok if you ask me...

[TVR Beaver]

Yup.. all looks okay.. can't remember how they had got it wrong but somehow it was pumpimg backwards?????...
Id try it without the stat to see if you get any more air out... but that said, your back to square one when you have to re-fit the thing?...
I've run my small pipe from the swirl pot to the header tank on top of the ARB.. Makes messing a whole lot easier.. you can do this be putting two spacers under the expansion tank mounts moveing it up about 10mm....
.
is the noise the only issue.. or are you getting increased pressure and / or coolant loss?

[Marty V8]

TVR Beaver said:

Yup.. all looks okay.. can't remember how they had got it wrong but somehow it was pumpimg backwards?????...
Id try it without the stat to see if you get any more air out... but that said, your back to square one when you have to re-fit the thing?...
I've run my small pipe from the swirl pot to the header tank on top of the ARB.. Makes messing a whole lot easier.. you can do this be putting two spacers under the expansion tank mounts moveing it up about 10mm....
.
is the noise the only issue.. or are you getting increased pressure and / or coolant loss?

Re-routing the inlet pipe to the header tank sounds like a relatively easy thing to do to rule out the possibility of a squashed pipe - good idea that

Its just a noise as far as I can tell but its loud enough that it can be heard over the engine when the car is moving. When it was doing it last time before I changed the stat to its current one, I could feel the water bubbling away in the pipe between the stat housing and the swirl pot. Maybe theres still air in there, but other than putting a bleed into that pipe (which I dont intend to do), I dont know how to get rid of it.

I'm not losing any coolant, but its a bit unsettling to think that there is an air lock in it somewhere that might pressurise the system more than it needs to be.

[TVR Beaver]

That is very loude for air or boiling water??....
.
before you move the bottle.. see if it's working... give the top hose a squeze and see if the level changes in the expansion tank whilst looking into it...
.
if you do move it.. it may catch the bonnet a tad as it opens.. so take care...
I did mine as it's much easier to remove this way

[Loubaruch]

Are you sure its the cooling system making the loud clack?
My engine regularily emits this type of noise but its the SS exhaust manifolds/ pipework expanding and contracting as the engine temperature changes. Its a loud distinctive clack very noticable above the normal engine racket.

[jimed]

I'm not an expert but maybe if you have only done 150 miles and the heater has not been on during the actual runs it might be worth trying that and also seeing if a few more miles does the trick as sometimes the last of the air can take a little while to work its way out. What is happening in the header tank - is the level stable of has it dropped a bit - if dropped maybe there is still a little air getting out or maybe as said above its not the water system making the noise?
Jim

[Rob_the_Sparky]

Not sure about the noise but it took absolutely ages to clear the air from my system after the stat and hoses change. However, I knew there was air in there as each time I drove the expansion dropped a bit and squeezing the top hose afterwards gave a bubbling noise. Took yonks but eventually stopped. I got naughty in the end and forced out the last bit of air by slowly releasing the pressure cap with the engine hot (very carefully!).

Never heard the noise you describe though, not convinced it is the same thing...

[Marty V8]

Thanks for all the replies.

Beaver - thanks for the tip re the expansion bottle.

Lou - I know the exhaust sound you are referring to but it isnt that. Its as sure as I can make out coming from the cooling system.

Jimed - you may have a point as Ive not done many miles in it with the heater open. I have had the car running with it open and it does get very hot, but its definately worth a try.

Rob - I cant get any more water into the swirl pot when its cold or hot i.e. with the stat open.

I may try the hosepipe in the top heater hose as someone previously suggested.

Thanks again for all the sugestions. Please keep them coming.

Cheers

Marty

[Marty V8]

Hi,

Just an update on the thread.

Ive now got approx 450 miles on the motor since rebuilding it and the weird noise from the cooling system has not re-occurred at any time during the last three journeys which probably total 120 - 150 miles.

I had tried to put some more water into the heater pipes at the back of the engine as suggested but these pipes were full. However further tightening of the jubilee clips on the silicon coolant hoses has seemed to have solved the problem. I was surprised at how much more I could tighten these jubilee clips as I had thought I had got them really tight already. If this noise doesnt re-occur I can only surmise that it was sucking in air from one of the hose connections and then this air was bubbling at the high point in the hose between the thermostat housing and the swirl pot.

Fingers crossed...

Thanks all for the help and advice. Damn good forums these

Cheers

Marty

[jimed]

Glad it is now OK. Silicon hoses do need to be retightened a few times after they are fitted but they settle down; maybe worth going round them again until they don't loosen. (I went round my hoses the other day to check them and got at all the clips except the heater connections behind the engine - any advice about getting to those??)
Jim

[Marty V8]

jimed said:

Glad it is now OK. Silicon hoses do need to be retightened a few times after they are fitted but they settle down; maybe worth going round them again until they don't loosen. (I went round my hoses the other day to check them and got at all the clips except the heater connections behind the engine - any advice about getting to those??)
Jim

Either one of those flexi-drive hose clip screwdrivers or if you cant get in to them then you possibly may have to take off the n/s rocker cover to get at those, which in turn means taking off the plenum etc etc.

[jimed]

Thanks Marty - I do have one of the flexi drive things - absolutely brilliant for getting in to clips - I'll have another look at the heater ones. I've not replaced any hoses so hopefully all will be OK anyway I was just checking them to ensure they were tight.
Jim