Rolls-Royce and Bentley Forums banner
61 - 80 of 112 Posts

·
Registered
Joined
·
56 Posts
Discussion Starter · #61 ·
It's possible that I am being really stupid here. I am getting bubbling in the header tank when the engine gets up to temperature (about 20 minutes idle) but not before. The reason I was concerned is because the old top hose was perished and was bulging so I replaced it at great expense (for a hose!). I have been terrified of splitting the new hose so I've been observing the bubbling with the radiator cap off. Is the bubbling occurring BECAUSE the radiator cap is removed?? I only just considered this after coming across a number of posts on various car forums saying that the coolant will boil if it is not under pressure.
 

·
Registered
Joined
·
3,589 Posts
Have you removed and tested the thermostat? It may be stuck closed. I would also check the steam valve in the header tank under the round plate held by BA2 screws. There is a cover seal and internal seal around the steam valve. The steam valves are made od thin brass and rather fragile. Looks= for a crack in the valve.
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #63 ·
Hi - I am fairly sure that the thermostat is working ok as the radiator is getting hot as it should be. I actually tried to check it today and broke one of the bolts in the housing (aarrg!) Another job.
Pressure is building up in the top hose and it gets very firm - I wondered more if the steam valve may be not venting rather than leaking - does that ever occur please?
Gas Electric blue Metal Circle Machine
 

·
Super Moderator
Joined
·
904 Posts
That thermostat has failed, replace it with a Stant 13558. The lead/bismuth alloy fusible plugs are gone so the thermostat will no longer function as intended. I suspect it has seized shut and the only coolant passing through it now is through the round holes hence you are only getting marginal cooling.
 

·
Registered
Joined
·
2,035 Posts
If your top radiator top hose is a lot hotter than the bottom hose that's normal provided that the temperature of the top hose is'nt above boiling temperature. The coolant from the top hose passes through the radiator and should come out cooler at the bottom. Check for air locks by raising the front of the car and turning the heater to defrost while running the engine with the header tank cap removed, that should help to expel any air, giving the top hose an occasional squeeze helps to speed up the air bleeding process.
 

·
Registered
Joined
·
636 Posts
Hi - I am fairly sure that the thermostat is working ok as the radiator is getting hot as it should be. I actually tried to check it today and broke one of the bolts in the housing (aarrg!) Another job.
Pressure is building up in the top hose and it gets very firm - I wondered more if the steam valve may be not venting rather than leaking - does that ever occur please?
View attachment 30848
That's not too difficult to get out if you're patient, here's is what I do, it may not be the best way, but the alternative of using an easy out (which never works _ the break off inside the bolt) or any attempt of drilling it out, causes the bit to wonder of in the soft aluminum.

Remove the thermostat and clean all the gasket material off, this will expose the inside to get at the broken bolt.
Get a small ball-peen hammer, a can WD-40 and a tourch with MPS gas.
Heat the area where the stud is, inside and out and spray WD-40 at the base where the break is.
Do this until the WD-40 is all burned off.
Continue heating until it's hot as possible _ it will reach a point where it will only get so hot as the aluminum housing will dissipate a lot of heat.
While it's hot, take the hammer and gently tap if from all sides and on the top.
Spray more WD-40 and it will sizzle at first and burn off _ add more until it stops sizzling.

Reheat and repeat _ after 4 cycles of this get a good pair of Vise-Grips and gently rock the bolt _ do not try and force it if it won't come, or it may snap again.

This will eventually work, as the heating, cooling and tapping will break the bond of rust and aluminum oxide.
When it starts to come, just don't force it out _ add lots of WD-40 and work it down the threads carefully.

If the thermostat sender is near by, remove it as the heat will destroy it.

Also, be carful not to damage the deck of the thermostat housing with the Vice-Grips

I had this very situation where a water pump stud on my Jaguar would not come.
After an hour it did come out with no harm to the aluminum or timing chain cover, or even the stud.
I didn't have to use Vice-Grips though as the stud still had it's threads so I used two nuts tightened against each other to rock the stud back and forth.
 

·
Super Moderator
Joined
·
904 Posts
The absolute best and easiest way to remove a broken stud requires the use of a MIG welder. Place a nut one or two sizes bigger than the stud over it so the bottom of the nut rests on the housing. MIG weld the stud to the nut getting as much weld wire into the nut and around the stud and build up a mound on top. You want to get it as hot as possible quickly so the heat travels down the stud expanding it. Allow it to cool completely then try cracking the nut back and forth a tiny bit working it back and forth further each time and it will usually turn out first time. Some acetone and ATF mixed 50/50 around the base can help loosen it. WD40 is not really a very good penetrating oil but the acetone/ATF mix works very well. A MIG welder is the easiest, but arc, TIG, and gas can be used too. Don't try turning the welded nut until the weldment is completely cooled down to allow maximum shrinkage of the stud.
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #70 ·
Wow thank you so much for your detailed responses. I'll have a go at the stud this weekend. Is it possible then to tell that the thermostat is shot from the photograph? I will defiantly change it.
 

·
Registered
Joined
·
3,589 Posts
WD-40 is ineffective as a bolt loosener. It is a protectant. Use Kroil or 50/50 mix of ATF and acetone to really see results
 

·
Registered
Joined
·
2,035 Posts
Wow thank you so much for your detailed responses. I'll have a go at the stud this weekend. Is it possible then to tell that the thermostat is shot from the photograph? I will defiantly change it.
The large holes in the thermostat are left when the lead pellets dissolve due to overheating if a thermostat fails to open in time. It's a fall back safety device to allow coolant to circulate through the holes left behind when the lead melts.
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #74 ·
The thermostat seems to start opening at about 90 degrees, and doesn’t open very much - this is the first time I’ve put one in a pan and not really sure what to expect.
try
Temperature Scale Gauge Measuring instrument Tool

Wheel Automotive tire Motor vehicle Automotive lighting Alloy wheel
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #76 ·
Yes I definitely will but struggling to find a Stant 13558 or equivalent over here in UK. They cost over £100 from the usual RR suppliers. My old Shogun was running for 8 years before I realised it was missing it's thermostat!
 

·
Registered
Joined
·
636 Posts
The thermostat seems to start opening at about 90 degrees, and doesn’t open very much - this is the first time I’ve put one in a pan and not really sure what to expect.
try View attachment 30854
View attachment 30855
The thermostats lead plugs have melted out, there was no point really in checking it on the stove other then to you show you a faulty thermostat.
At least you have that for reference.

If you can't find one, and they seem to be hard to find, I can check my local auto parts store and I'll send it to you.
You may PayPal me the cost + shipping, they're not expensive.
 

·
Registered
Joined
·
842 Posts
I've just had a look round (in the US) and all the usual sites have sold out. Napa have the 136 equivalent in stock so I panic bought one for the future - 24 bucks. Interesting thing is when I input my vehicle details (74 SS1) it actually said it was a guaranteed fit - they must have read Brian's resource file.

Isdyl - if you can't find one in the UK I'll ship one to you.
 

·
Registered
Joined
·
56 Posts
Discussion Starter · #79 ·
Thank you for your very kind offers. I'll do a bit more phoning around on Monday just to see if I've missed anywhere. Equally if there is anything available in UK that anyone is struggling with I'm happy to post over the pond too. Just let me know.
Also am I right in thinking that when the thermostat opens, the plate pushes down and blocks the bypass tube at the bottom? So running it without a thermostat would be a bad idea?

I'm still very patiently trying to remove this stud, but it's becoming clearer that ultimately I'm going to end up having to drill it out. I've managed to put a thread on it using a die and locked a couple of nuts on it. Still gently wiggling it and using penetrating oil. I applied a bit of heat with the propane torch but even with plenty of protective boards around it I got scared of melting something.
Water Fluid Liquid Automotive tire Gas
 
61 - 80 of 112 Posts
Top