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Ok, here's one for you.

 

New (to me) TR4A with a few cooling issues. Recently flushed with Bars. Still suspect rad might need a recore.

 

Anyway, just recently it sprang what I thought was a leak in the top hose. Replaced top hose. Replaced thermostat gasket at the same time and discovered there was no thermostat.

 

Started her up and seemed ok, so went for a 15 min run - discovered on return it had exactly the same leak as before - leaking badly onto the pulleys/fan and in turn being spread all over the engine bay. It's leaking between the underside of the thermostat front cover and the top hose - almost as if there is some kind of back pressure or build up in the rad that is forcing coolant to build up in the hose. Must be at a fair pressure as the hose is good and tight and I cleaned the thermostat cover before connecting the hose.

 

I did notice a couple of days ago when I was investigating the original leak that if I ran the engine with the rad cap off there was a lot of "disturbance" ie choppy water in the neck of the rad - maybe evidence that is not flowing down the rad properly?

 

One other thing - obviously I need to add a thermostat, however could the fact that there is one missing be letting far more coolant into the hose and rad than it can cope with ie too free flowing? Or does it really look like the rad is blocked up?

 

Who sells the proper thermostat with the shroud to block off the bypass pipe?

 

cheers, andy

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Hi Andy,

 

Can't help with the thermostat as they are difficult to find. Alternatively fit a standard t/stat and block the bypass hose with a cork or similar with a 1/4 inch hole in the centre.

 

The top hose is prone to leaking, you could try a second jubilee clip, but are you sure that it is leaking. If the water pump seal leaks, it drips water on to the inside of the pulley and gets spread all over the inner wings, bonnet and onto the t/stat housing.

 

I don't think that the missing t/stat will be causing the leak.

 

Hope this is of help.

 

Graeme

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Hi Andy,

 

Can't help with the thermostat as they are difficult to find. Alternatively fit a standard t/stat and block the bypass hose with a cork or similar with a 1/4 inch hole in the centre.

 

The top hose is prone to leaking, you could try a second jubilee clip, but are you sure that it is leaking. If the water pump seal leaks, it drips water on to the inside of the pulley and gets spread all over the inner wings, bonnet and onto the t/stat housing.

 

I don't think that the missing t/stat will be causing the leak.

 

Hope this is of help.

 

Graeme

 

Thanks Graeme, will check the pump - do you mean the seal between the impellor and the bearing housing or the gasket between pump body and bearing housing?

 

have dug out a tstat so will fit that tomorrow - guess if the top hose area is the culprit it shouldn't leak until the tstat opens.

 

Alec - have begun to realise that one way or another I'm going to be better off whipping the rad out and seeing what is really going on with it. Cheers, andy

Edited by 67_gt6
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Hi Alec - car is in the street just now and no access to a hose. Probably just going to drain it and take it into the bath (unconventional I know but will be able to get decent flow into it there). Have flushed it once already in situ so want to see if it is actually blocked before doing it again. Cheers

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Hi Andy,

 

Try Moss US, I think these are a 'new' product and not available via Moss Europe: http://www.mossmotors.com/Shop/ViewProduct...teIndexID=47023

 

Cheers

Andrew

A thermostat without a sleeve can be used, when you partially block off the by-pass by a plug with a central hole of about 10mm (as described in Net Nuggets - Teri Ann's TR3)

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Andy,

There is a sleeved thermostat on ebay but it's listed under TR2 only. I use exactly the same type and have had no problems at all.

Cheers, Nigel (with TS952)

 

Item No. 4651705191, I know the chap has several so may be worth an email to him.

Alec, a quick one - without a stat you still have to blank the bypass hose don't you, I was told you did but maybe another bit of false info - Nigel

Edited by Nigel Lay
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Thanks chaps, radiator is away being recored now so hopefully will have some progress next week.

 

On a sidenote, I have a bit of weeping from the block tap - I'm tempted to remove the housing and tap and replace as someone has fitted my housing upside down (hence the tap is wired in upside down, all a bit Heath Robinson). Is there a better spec housing/tap available? Is the housing likely to be awkward to remove? - thinking particularly of corrosion issues due to the two types of metal in contact.

 

Thanks

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............without a stat you still have to blank the bypass hose don't you, I was told you did but maybe another bit of false info

 

HI Nigel

 

Your info was partially correct, as you can also simply:

 

1. Cut out the centre mechanical parts from a modern wax type thermostat and fit it: this then acts as a restrictor and backs up the water allowing it to cool in the rad. Without it, the water would just pass through the rad limiting cooling affect.

 

2. Fit a restrictor in the bye-pass hose; otherwise the water will just circulate and "bye-pass" the rad for the most part. Without the restrictor there is a chance of creating local hotspots in the engine with consequent results.

 

3. For the restrictor, I used a washer with a 1/4" hole (GHF314 from Moss is ideal) or you could use a 10p piece and drill it with either 1/8th or 1/4". You will need to use a second jubilee clip behind the washer to keep it in place and prevent it slipping down the hose under pressure. Ensure the washer/coin is fitted hard against the bye-pass housing outlet inside the hose.

 

With the above measures, and the other usual (e.g. rad ducting, Opitmax with Castrol Valve Master Plus etc),

my 3A runs at 170-180f with outside temps up in the mid-eighties and only in heavy traffic does the Kenlow need to come on now. I've set this at 185f.

 

Cheers

Andrew

Edited by Andrew Smith
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Ok, here's one for you.

 

New (to me) TR4A with a few cooling issues. Recently flushed with Bars. Still suspect rad might need a recore.

 

Anyway, just recently it sprang what I thought was a leak in the top hose. Replaced top hose. Replaced thermostat gasket at the same time and discovered there was no thermostat.

 

Started her up and seemed ok, so went for a 15 min run - discovered on return it had exactly the same leak as before - leaking badly onto the pulleys/fan and in turn being spread all over the engine bay. It's leaking between the underside of the thermostat front cover and the top hose - almost as if there is some kind of back pressure or build up in the rad that is forcing coolant to build up in the hose. Must be at a fair pressure as the hose is good and tight and I cleaned the thermostat cover before connecting the hose.

 

I did notice a couple of days ago when I was investigating the original leak that if I ran the engine with the rad cap off there was a lot of "disturbance" ie choppy water in the neck of the rad - maybe evidence that is not flowing down the rad properly?

 

One other thing - obviously I need to add a thermostat, however could the fact that there is one missing be letting far more coolant into the hose and rad than it can cope with ie too free flowing? Or does it really look like the rad is blocked up?

 

Who sells the proper thermostat with the shroud to block off the bypass pipe?

 

cheers, andy

 

Andy

 

You asked about thermostats. I have a brand new 74 degree thermostat which I obtained from Rimmer Brothers which I find I do not need - you can have it at cost plus postage. (Price was £2.98!) Alternatively if you want the 82 degree thermostat, Rimmers can supply - tel no (Lincoln) 01522 568000. The 74 degree item is supposedly for tropical conditions, but a 70 degree thermostat is called up in the TR4A workshop manual and if you have been running hot this may be preferable.

 

Regarding the leak, there is a gasket where the thermostat housing is bolted to the head. This may be the culprit as it sounds as though it is in the right area. Again, Rimmers can supply. It is worth fitting new gaskets when having the thermostat out and if you remove the housing from the block.

 

Hope this helps, sorry about the long intro but new to the site.

 

Horse

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At the risk of stating the obvious, if you suspect pressure build-up, I assume you have the correct 7lb radiator cap fitted? Even if you have, it's worth trying a new or borrowed known good one, just in case it's not opening early enough. In my experience, if you've got a pressure problem you usually get the overflow bottle itself overflowing and water spraying everywhere from the hole in its cap.

 

One other remote possibility is the thermostat housing itself which can become porous. I have also had one which had corroded and started to break up inside the radiator hose so that it leaked under pressure.

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