Cooling a DAX Chevvie V8

[chris27_blue]

Just a thought.
You're not overfilling the expansion tank are you?
Only fill it half full, when cold.

I've got an annoying leak on my 302.
just struggling to pinpoint it behind the water pump somewhere.

Good luck with your leak- they are so annoying. My brother in law with his MG doesnt bother trying to fix any small fluid leaks- just old carpet on garage floor. LOL.

Good thought about expansion tank level, but no. Only half full expansion tank or slightly less.(Measured with an old fashioned measuring stick) Learned my lesson on that last year. Because my coilovers on front were set at the absolute lowest (Now raised) i had an interaction with a bit of wood on road that hit the bottom rad exit pipe out of kilter- not circular. Its either change the rad (Body shell off, swap out for a new rad at over £400) or repair. am going for the repair option first :-)

And as for sealant, its a semi hardening plastic compound that I have applied only liberally to smooth out any small imperfections, that lead to drips. helps, but doesnt resolve.

Still. am keeping to head scratching, and trying anything. Ha!

[Chris]

Ended up putting the car into Pilgrim Motorsports after trying a couple times to resolve myself, and getting wound up.

They replaced bits, engineered a solution to the buckled rad exit pipe, pressure tested, road tested and after almost 3 weeks gave it back (After charging lol)

So, had a nice 70 mile drive, left it overnight, and theres was the same place leaking again.

Trying to sort myself again (I mean cmon, its only a couple teaspoons water leak) with sealant and very slightly tightening the mikalor clamp every day there is a leak.

The leak only occurs overnight when it gets colder- it can be left for 10hrs during the day, even after a drive, and it doesnt leak. Is it just the hose contracting as it gets cold and leaking a bit?

Any suggestions for a solution to overcome the issue, welcomed :-)

I see that you mention sealant, are you referring to a coolant additive to address the issue ?
Or going through the motions of stripping, cleaning then using a good sealing compound on reassembly of manifolds etc ?
Obviously that would be the preferred method.
In a past post I did mention 'k' Seal that I used to address an annoying leak from a core plug behind the flywheel on my S R with success, I am definatly not suggesting you do the same.
In the past there has been dreadful results with some of the earlier types and would state this was the first time that I had used this kind of stuff.
The sealer that I have used seems to have a reasonable write up and has been know to used in the racing world to address these annoying issues, not that would be admitted !
Personally I would not use this kind of sealant for anything other than weeping core plugs !
Hope you arrive at a solution before it drives you nuts !

Chris.

[Kev Davies UKCC Membership]

Just a thought.
You're not overfilling the expansion tank are you?
Only fill it half full, when cold.

I've got an annoying leak on my 302.
just struggling to pinpoint it behind the water pump somewhere.

[chris27_blue]

Ended up putting the car into Pilgrim Motorsports after trying a couple times to resolve myself, and getting wound up.

They replaced bits, engineered a solution to the buckled rad exit pipe, pressure tested, road tested and after almost 3 weeks gave it back (After charging lol)

So, had a nice 70 mile drive, left it overnight, and theres was the same place leaking again.

Trying to sort myself again (I mean cmon, its only a couple teaspoons water leak) with sealant and very slightly tightening the mikalor clamp every day there is a leak.

The leak only occurs overnight when it gets colder- it can be left for 10hrs during the day, even after a drive, and it doesnt leak. Is it just the hose contracting as it gets cold and leaking a bit?

Any suggestions for a solution to overcome the issue, welcomed :-)

[JON1D]

You can get 45 deg bends and just make sure the lengths are long enough. I would go stainless and get some small welds to form the bead to hold your hose on. If you go ali again check lengths and most come with beads.

https://www.autosiliconehoses.com/alloy-elbow-pipe-intercooler-performance-automotive-aluminium-tube.html

They do stainless. you say 48 i.d  51mm O.D. will be close

https://www.autosiliconehoses.com/stainless-steel-elbow-pipe-exhaust-performance-automotive-tube.html

I use Mikalor champs now W4 all stainless as perversely stated,

You need the correct size range. W4 are the best 316 marine grade stainless.

https://www.autosiliconehoses.com/hose-clips-t-bolt-hose-clamp-w1-zinc-plated-w4-stainless-steel.html

Filling slow and open up any caps.If you have a heater it might sit high and make sure it is open when filling. Then run it with the caps off until the thermostat opens switch off and refill as the level will drop . Job done.

[chris27_blue]

Anyone have suggestions where to get the short bottom radiator connecting pipe (To steel hard pipe) or is it just buy a piece and bend it? Looks like 48mm Internal diameter, and looks like a 45deg angle would do it.

Best clips as an upgrade to standard jubilee clips? My jubilee has dug into the silicone rubber and caused a minor leak, which is getting worse all time. Old pipe i think, although it may have been knocked once or twice on those horrible speed bump things.

Any tips on draining the system? Just drain/ refill? Or any vent screws anywhere. Not sure how to tackle any air lock if i get one.

Ive also found Prestone coolant seems much hardier than OAT Pink stuff?

[CobraPaul]

Yes you are correct it basically jumps the relay, the connection on my set up of two relays and fans is spade
terminal  no 86 on the relays that is switched and fused, I haven't bothered with a separate w/l .
I have used piggy back crimp connectors in this case due to fact that there is only very small current involved.
As for main connections I have used decent gauge wire and solder type connections, you will need to do this
to avoid cooked terminals .

Thanks.
I have an odd setup on mine, clearly.
I have the main relay for the fans under the dash, but another relay in the engine bay providing 2 fan connectors. Both fans only ever came on together, and I'm trying to decipher the wiring.
I am changing to a single 16" Spal fan but would ideally like an override too.

[JON1D]

Just did a antifreeze change and before I did a pressure test on the system (comes with hand pump and adapters in a plastic case) up to 13lbs as the system will hold.
I always had an annoying leak from somewhere thinking it was the rad core. It turned out to be the top hose to rad connection just needed tightening. I fitted Mikalor champs now W4 all stainless. After a refilling the system, I found two minor weeps from top hose to block new gasket and another loose jubilee.

[Chris]

Hi!
Interested to know how you wired in an override switch. Any diagrams?
I assume it just jumps the relay?

Yes you are correct it basically jumps the relay, the connection on my set up of two relays and fans is spade
terminal  no 86 on the relays that is switched and fused, I haven't bothered with a separate w/l .
I have used piggy back crimp connectors in this case due to fact that there is only very small current involved.
As for main connections I have used decent gauge wire and solder type connections, you will need to do this
to avoid cooked terminals .

[CobraPaul]

Hi!
Interested to know how you wired in an override switch. Any diagrams?
I assume it just jumps the relay?

[chris27_blue]

Thanks Dek
Ended up just removing the thermostat cover. Had a little bit of silicone gunk as a seal, no O ring
So after cleaning the old gunk off, put a new gasket on, with a new bit of water pump silicone, and it seems tickety boo now.

Have to move on to the Brake/clutch recervoir fluid loss now.

Only minimal, and thought it was the (not very well sealed) reservoir cap.
Am not definite it is that, am monitoring.
If not (Have checked both brake and clutch master cylinders) then guessing it may be clutch slave or one of the brake calipers. Not sure I am agile enough to be cavorting under a car looking at brake cylinders/ clutch slaves, but will give it  try.

[Dek]

As an extra to this thread on a cooling issue, my Chevvie small block thermostat housing appears to be leaking

Firstly, any clarification on where the serial numbers are to confirm date/age of the 350 ci engine?
Nearside engine toward bulkhead down low?
And offside near front up high? Havent looked yet

Am thinking the engine type/age will clarify which type of thermostat gasket it requires, as i believe there are at least x 2 dependant on age of engine.

Thanks

I don't think you probably need to know the age of the engine. From memory there's probably only 2 types, one with a straight outlet and the other with a raised outlet. I would take it off and inspect the mating surfaces and see if it's got a gasket or "O"ring to seal it. Modern replacements tend to have "O"rings. Steer clear of cheap chrome Chinese replacements. They'll corrode and not last long. Billet aluminium look good and last but more expensive. If the mating surfaces are true and clean up well you might be able to seal with silicone RTV without a gasket or you could make one easily. Have a look on RealSteel.

[chris27_blue]

As an extra to this thread on a cooling issue, my Chevvie small block thermostat housing appears to be leaking

Firstly, any clarification on where the serial numbers are to confirm date/age of the 350 ci engine?
Nearside engine toward bulkhead down low?
And offside near front up high? Havent looked yet

Am thinking the engine type/age will clarify which type of thermostat gasket it requires, as i believe there are at least x 2 dependant on age of engine.

Thanks

[Chris]

Had a lively drive around this evening, and both top and bottom hoses are warm.

Temperature stayed around 82, funny enough after removing a bit of coolant so expansion tank is just under half.

Am hoping that changing out my fan switch may resolve my issue. TBC

EDIT Supplemental:
Hi Chris ,
Took mine out for a spin yesterday, it was a reasonable warm day with no overheating issues, will add that I have
never really had any other than engine got a bit hot for my comfort when breaking in the camshaft !
There is something that I will add that may help with regards to keep any air locks out of your cooling system .
I have in my 82 deg c thermostat and this is not a wind up, is what they call a "jiggle pin" that is within the stat .
This may not be any use for your motor but this was a proper fix for my old Buick (RV8) .
Chris.
Fitted a new Rad Fan switch, and tickety boo that fan now comes on at about 85deg, and assume it turns off soon as 80deg reached. May fit a signal lamp to it so i cant tell when fan is on and not on

Confirmed the thrmostat is working fine

Just an overide switch to fit, for piece of mind

Hopefully issue solved

Hope the thread has helped someone, and thank you all for the replies

[chris27_blue]

Had a lively drive around this evening, and both top and bottom hoses are warm.

Temperature stayed around 82, funny enough after removing a bit of coolant so expansion tank is just under half.

Am hoping that changing out my fan switch may resolve my issue. TBC

EDIT Supplemental:

Fitted a new Rad Fan switch, and tickety boo that fan now comes on at about 85deg, and assume it turns off soon as 80deg reached. May fit a signal lamp to it so i cant tell when fan is on and not on

Confirmed the thrmostat is working fine

Just an overide switch to fit, for piece of mind

Hopefully issue solved

Hope the thread has helped someone, and thank you all for the replies