Bleeding cooling system woes.....

[DrasticplastiC]

Some experienced advice would certainly be appreciated upon this. I have drained the coolant, had the radiator recored, flushed the system and refilled with a 40% antifreeze mix and deionised water.

Last Summer it had started to overheat on the top of a steep climb so I had topped it up and not used it since other than to keep it running every month.

I stuck a funnel in the top of the swirl tank and successfully bled the system, until fitting a new expansion cylinder cap. When the system pressurised I checked for any further air to be released on the radiator bleed bolt, but this time, fans running, no water came out. I took the bolt out, released the expanion cap, the level came up the cylinder, but still nothing at the rad bleed bolt.

I have been working on this for 2 hours this morning. I thought I had nailed it! I heard these engines can be hard to bleed but I am surprised by this.

It made me wonder if the head gasket is leaking. I concluded water loss due to a corroded rad was the problem last year.

My question is wjen heas gaskets go on these is it really obvious? I have no mayonnaise, the oil is clean... The fans were cutting in amd it was not overheating. I thought about doing an exhaust gas in coolant test.

Any advice from experience would be appreciated!

[SMB]

You should really be able to get to a stage of some water at the radiator bleed screw even when cold by squeezing the pipes. No water in the rad is probably why it's overheating. I assume from the photo the coolant temp sensor for the fan is in the swirl pot not the radiator. So that is heating suggesting thermostat is working as designed

So some questions

Does the heater in the car get hot?
Are the steel pipes in good condition?
Did you squeeze the hoses regularly whilst filling?
Did you do the refil on flat ground or nose raised?

No water at the rad screw suggests a blocked pipe or radiator. But it could still have air in it.

[DrasticplastiC]

Hi. I regularly squeezed the top hose. I properly bled the rad bleed bolt several times, the issue of all that air started when I pressurised the system. I had periodically revved the engine steadily at 2500 rpm to expel air from the funnel. The pipes are in good order. The inside heater was working last year, the fan motor is shot at the minute so I can't tell..... Surely if the head gasket was starting to go I'd have a lot of bubbling in the funnel all the time.....?

[DrasticplastiC]

I've filled it on flat ground. As I said it is a new radiator I have just fitted.... It is not overheating.....

[SMB]

DrasticplastiC said:

Hi. I regularly squeezed the top hose. I properly bled the rad bleed bolt several times, the issue of all that air started when I pressurised the system. I had periodically revved the engine steadily at 2500 rpm to expel air from the funnel. The pipes are in good order. The inside heater was working last year, the fan motor is shot at the minute so I can't tell..... Surely if the head gasket was starting to go I'd have a lot of bubbling in the funnel all the time.....?

The top hose is mostly air until the system is nearly full, so just squeezing that won't move air trapped lower down.

Suggest you let it cool before adding more water

Fill the expansion tank to a third full and put the cap on, if you leave it off that tank will just fill up.
Put heater control to hot
Take out radiator screw , fill with the funnel fitted squeezing all pipes esp those at the bottom of the swirl pot and the return from the rad, you should see some water at the rad. Once you think you have done enough do it again. If you can squeeze the rubber hoses at the back of the engine going to the heater

Squeezing a few times is never enough.


Once you see some water at the rad, replace the bleed screw have water in the funnel and try to start it, feel the hoses as they heat up, thermostat to swirl first then, swirl to rad, then rad to pump, they should get warm in turn. If one stays cold water isn't getting around

Re head gaskets , previous overheating may have caused issues but if there is no water at the rad , that will cause overheating first. Saying the heater worked last year doesn't mean much as you have drained and refilled now.

[Belle427]

I’d try to fill the radiator too.

[DrasticplastiC]

I'll consider what you said, please note the photo is of the engine running at 85°C having bled the rad bleed bolt but before pressurising the system.....

[SMB]

Belle427 said:

I’d try to fill the radiator too.

Yes you could, I'm used to doing both Griffith and Chimaera and there's little access room to the rad bleed screw on a Griffth for filling.

[SMB]

DrasticplastiC said:

I'll consider what you said, please note the photo is of the engine running at 85°C having bled the rad bleed bolt but before pressurising the system.....

I get that but you should have water at the rad bleed screw, no water means there is air in the system. A head gasket leak that causes air to enter the coolant from the combustion chamber will cause overheating, which you say you don't have, so the main issue is air still at the radiator which suggests it's not fully filled with water. It may not overheat now but on a hot run a not full radiator = non efficient cooling system.

[s p a c e m a n]

I've had to do this several times now and it's so much of a pig I start off filling it all with a garden hose. Get the car warm with whatever water you've managed to get in there so that the thermostat is open. Get your garden hose with the standard cheap fat finger shaped attachment on the end and it will screw into the top of the alloy swirl pot if you force it, you can then turn on the hose and pressurise the system opening all of the bleed screws as you go.

[Belle427]

I always find it better to go for a short blast as long as it’s not overheating.
The technique here toward the bottom of the first page seems to be well used.
https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Classic Chim]

Without reading all the replies, once you have bled and got constant water from new rad have you loosened the hose on the n/s of inlet manifold to expel air that can be trapped up there. If your heater fan doesn’t work can you confirm if the two steel pipes above the battery are getting hot.
It’s a good idea to raise the nose of the car as high as poss to help fill the heater matrix etc but most TVR people don't bother.
Finally are you sure the thermostat is working properly.

Smell the coolant in your expansion bottle, if engine gases are present you’ll smell it.