Correct coolant replacement - GT6

[BenWW]

Hi all,

So my GT6 on the last few runs has been running hot. 

Starting with the basics I thought I would drain, flush and replace the coolant as it's one thing I can't guarantee has been done for a while. I was going to replace the thermostat whilst I was at it.

I know there is a tendency for the block to gunk up and sighted the drain hole for that.

Question is, can I drain most of the fluid from the radiator with the drain plug (cap off) as I know what will happen if I pull free the main hose from the base of the radiator..  I'll end up with it all over the bay.

I was going to drain down as much as I could, add the deionised water, then the powerflush, top up with water and run for 10 minutes. Then drain down again and refill with new bluecool.

Am I missing anything?

 

Ben

[Colin Lindsay]

You can siphon limited amounts from the radiator, you can only really get as far as the top of the tubes. If there's no drain tap at the bottom of the radiator, nor one on the side of the block behind the exhaust, then removing the thermostat housing will enable you to drain more. For best results though you really need to remove the bottom hose and flush the system out with a hose, inserted from the top downwards and the bottom up, as many times as it takes.

[BenWW]

42 minutes ago, Colin Lindsay said:

You can siphon limited amounts from the radiator, you can only really get as far as the top of the tubes. If there's no drain tap at the bottom of the radiator, nor one on the side of the block behind the exhaust, then removing the thermostat housing will enable you to drain more. For best results though you really need to remove the bottom hose and flush the system out with a hose, inserted from the top downwards and the bottom up, as many times as it takes.

Thanks Colin.

Any other common faults which could lead to the overheating or do you think this is a good place to start?

[johny]

What condition is the radiator in? The fins start to deteriorate over time especially on the front face and these do dissipate a lot of heat.

The other aspect is how much heat is produced by the engine. If its running with a weak mixture, either through adjustment or additional air getting into the intake side, it will produce more heat which of course means the cooling system has to work harder...

[dougbgt6]

1 hour ago, B5NWW said:

as I know what will happen if I pull free the main hose from the base of the radiator..  I'll end up with it all over the bay.

Back flushing is well worth it but makes a mess! So do it outside, bottom hose off, drain. Garden hose in the top, run till water comes out clear. There may be crude in the block drain and this may be winkled out with a small screwdriver or wire coat hanger. but this is not imperative, the drain plug is in a reservoir to the side of the main water jacket.  

Coolant, I think, should be replaced every 2 years, but I've gone MUCH longer  

Why do you want to change the thermostat? Wait and see what the back flush achieves, if not much, then change it. Make sure the thermostat has a small hole (sometimes with a crude ball type valve)

Doug

 

[BenWW]

51 minutes ago, dougbgt6 said:

Back flushing is well worth it but makes a mess! So do it outside, bottom hose off, drain. Garden hose in the top, run till water comes out clear. There may be crude in the block drain and this may be winkled out with a small screwdriver or wire coat hanger. but this is not imperative, the drain plug is in a reservoir to the side of the main water jacket.  

Coolant, I think, should be replaced every 2 years, but I've gone MUCH longer  

Why do you want to change the thermostat? Wait and see what the back flush achieves, if not much, then change it. Make sure the thermostat has a small hole (sometimes with a crude ball type valve)

Doug

 

Thanks Doug, sounds like great advice. I may have to move the car to an access with water to flush through properly then.

I was just thinking if changing the thermostat at the same time to rule that out. I'm guessing it isn't too much of an issue to change later on with new coolant in.

I haven't changed it in two and I don't honestly know when it was done before albiet it has been looked after so very well so unlikely to be much before.

[dougbgt6]

Ben,

Lots of threads on here were people say I did this, this and this, but now THIS is happening, what's wrong? One thing at a time is what the Grand Wizard Lewis has taught us! 

Doug 

[BenWW]

1 hour ago, johny said:

What condition is the radiator in? The fins start to deteriorate over time especially on the front face and these do dissipate a lot of heat.

The other aspect is how much heat is produced by the engine. If its running with a weak mixture, either through adjustment or additional air getting into the intake side, it will produce more heat which of course means the cooling system has to work harder...

Thanks Johny, sorry I missed this the first time. I'll be sure to take a good luck. If it doesn't look too great and no change after the coolant change I'll look to recore it. 

[BenWW]

25 minutes ago, dougbgt6 said:

Ben,

Lots of threads on here were people say I did this, this and this, but now THIS is happening, what's wrong? One thing at a time is what the Grand Wizard Lewis has taught us! 

Doug 

Yep, completely valid point. Probably best I tick one thing off at a time. Give it a good flush through and see how she gets on.

[Pete Lewis]

do make sure the engine was actually overheating and youre not chasing some daft gauge readings due to voltage stabiliser or sended problems

if you are planning a drowing in rusty water it is best to remove the thermostat you get unrestricted blast of flow 

to flush just use a couple of good mug fulls of cheap washing soda crystals    run for a week then fully flush 

afte 50 years  demin is a bit late ,

but check the block or cooant temperature before you jump in paranoid flushing 

old rads do end up with blocked tubes   a recore is the only solution  but if the rad is hot at the top and cold at the bottom its working 

gauges and therostat checks are the first and cheapest first job 

Pete

 

[Gully]

I flushed the cooling system on my GT6 a few weeks ago as I was fitting a new aluminium radiator. I removed the radiator cap first, then drained the block via the block drain tap (which flowed immediately - a good sign!). I then drained the rest of the system by removing the bottom hose (my old radiator didn't have a drain tap). I flushed the system thoroughly, using the garden hose, as follows:

1. Disconnected the heater supply from the heater valve and its return, so I could flush the heater matrix

2. Flushed the coolant return from the heater valve / banjo bolt

3. Reverse flushed the heater valve itself - this removed the most crud

4. Flushed the block via the block drain

I disposed of the old coolant properly, but the flushing water from the hose I simply allowed to exit into a bucket and splash at will onto the driveway and into the drain. Only a few rusty stains on the drive! I flushed until the water ran clear. 

New radiator is fitted and the heater is now working again (flow was poor due to build-up in the rad valve).

Gully

[Stratton Jimmer]

19 hours ago, Gully said:

I flushed the cooling system on my GT6 a few weeks ago as I was fitting a new aluminium radiator.

Out of interest, which aluminium radiator did you buy?

[Gully]

6 hours ago, Stratton Jimmer said:

Out of interest, which aluminium radiator did you buy?

This one: https://custommaderads.co.uk/product/triumph-gt6-aluminium-radiator/

Gully

[dougbgt6]

Blimy Gully! 

Plus VAT!

Out of interest, where do you park the car?

Doug

[Pete Lewis]

I could tell you for a decent fee   Hmmm  !!!!

Pete

[Wagger]

Don't worry over spilt milk. Actually, I have been told that is worse than residue from cooling systems.

I always save my coolant, let it stand, test it in the freezer, add new if necessary then return it less the silt.

Rarely had to do it in a 'Modern'.

[johny]

I thought its not so much the anti freeze properties coolant loses over time/use but its corrosion protection which in most of our cars is the more important factor?

[rlubikey]

1 hour ago, johny said:

I thought its not so much the anti freeze properties coolant loses over time/use but its corrosion protection which in most of our cars is the more important factor?

Yes, that's correct. Along with its high toxicity, the stability of the anti-corrosion agents is a major factor AGAINST using ethylene glycol antifreeze. This is why I use central heating antifreeze in my Spitfire, which is based on propylene glycol. It's nowhere near as toxic and the anti-corrosion lasts 20-years, not 2- or 3-years for Bluecol etc.

Cheers, Richard

[Wagger]

I should have said. Car was totally dry when my son found it. Nothing in the system at all. He put the new 'Pink' stuff in. It works in moderns with alumium, iron and some copper. No problems yet after two years. Heater works and it did not overheat in the heat of the summer.

I found some coolant years ago when clearing a generator factory. It was good for all metals and all temperatures and had 'Volvo' on the label. I had two gallons of it and it lasted 20years. Even used it in a central heating system. I did check the chemicals contained but cannot remember now what they were. It quietened the CH system considerably.

I was informed (years ago) that inhibitors coated the inner surfaces of cooling systems and this lasted unless other chemicals were used to rinse out the system.

I do not use the stuff that cats seem to love licking for that reason alone.

[Gully]

18 hours ago, dougbgt6 said:

Blimy Gully! 

Plus VAT!

Out of interest, where do you park the car?

Doug

It's gone up in price since I bought mine a few months ago. Inflation and all that! I'd still be winning if I'd bought new in the first place, as opposed to previously buying two re-cored ones, both of which leaked after a couple of years (one on the core, the other had a neck lip fracture).

Gully 

[BenWW]

On 10/10/2022 at 15:28, Gully said:

I flushed the cooling system on my GT6 a few weeks ago as I was fitting a new aluminium radiator. I removed the radiator cap first, then drained the block via the block drain tap (which flowed immediately - a good sign!). I then drained the rest of the system by removing the bottom hose (my old radiator didn't have a drain tap). I flushed the system thoroughly, using the garden hose, as follows:

1. Disconnected the heater supply from the heater valve and its return, so I could flush the heater matrix

2. Flushed the coolant return from the heater valve / banjo bolt

3. Reverse flushed the heater valve itself - this removed the most crud

4. Flushed the block via the block drain

I disposed of the old coolant properly, but the flushing water from the hose I simply allowed to exit into a bucket and splash at will onto the driveway and into the drain. Only a few rusty stains on the drive! I flushed until the water ran clear. 

New radiator is fitted and the heater is now working again (flow was poor due to build-up in the rad valve).

Gully

Thanks Gully. Here the heater matrix can be an issue. Will need to look that up in the manual, not sure I'd know that part.

 

[BenWW]

18 hours ago, dougbgt6 said:

Blimy Gully! 

Plus VAT!

Out of interest, where do you park the car?

Doug

Could have been more... https://www.radtec.co.uk/shop/makes/triumph/gt6/gt6-radiator/ benefit is these guys are local but still.. 😐

[Gully]

20 hours ago, B5NWW said:

Thanks Gully. Here the heater matrix can be an issue. Will need to look that up in the manual, not sure I'd know that part.

 

The two cooling system pipes that disappear into the bulkhead are the supply and return for the heater matrix - easy to pop off and flush. If you remove the hose from the heater valve end, that gives an easy (gentle!) push-on for flushing the valve. There's a useful diagram in the Workshop manual which illustrates the flow direction in each hose.

Gully

[Wagger]

I had to remove the heater valve on my Vitesse, soak it in washing soda overnight, flush with mains pressure (tap on a quarter turn) and then ease it on and off. It did clear and is still working one year on. I back flushed the heater after filling it using a hose and a funnel tied to the ceiling and a hot washing soda solution. Flushed that through and heater works perfectly. Loads of crud came out. Flushed that down the toilet, not the rainwater drain.

[PeteH]

Mine is out completely, so it got a bath in White Vinnegar, flushed a shed load of cr*p out of it and the matrix is now shiny as well. Hopefully that will combined improved the heat transfer?. Have been looking at a potential replacement motor to make a two speed fan.

Pete