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>Thermostat is in place and is correct. Have tried the 180 and the 165, both
>from Moss so they should be correct. Working on the gas tank now and when it
>is refitted, will start it up and see if the flushing solution will have any
>effect. Bypass hose is new and in place.
>
No. You are missing something important here. Re-read what I posted
earlier, below and the new text below that.
>> One thing we overlooked is your bypass hose. Do you have either a correct
>> skirted thermostat, or have you taken the precaution to partially block
>> your bypass? This may be the root of the problem altogether. Let me know
>> if you need more info on this.
The standard thermostat sold by Moss and TRF is not the same as the
original and can be marginal for our cars in hot weather. The original
thermostat had a skirt to block off the flow to the bypass hose when the
thermostat was open, eliminating a path for the water to return to the
engine without being cooled by the radiator. The intent of the bypass is
to allow the flow of coolant to continue through the engine when the
thermostat is closed, eliminating hot spots in the engine which would occur
if no coolant was flowing. Without a skirted thermostat or a partially
blocked bypass hose and an open thermostat, you will still get coolant
flowing through the bypass, up to 30% of all of the coolant, but it will
return to the engine hot, not having been through the radiator.
There are at least two solutions. I use both of these:
1. Get the correct skirted thermostat, either an original (expensive and
rare) or a reproduction. There is an outfit in CA (XK's Unlimited) making
them for the XK120 Jag. They fit the TR's. I've got a write up dealing
with their product somewhere. I'll find it for you in the next few days.
2. Place a restriction in the bypass hose. I use a washer which rests on
the metal nozzle on the block, within the hose, at the lower portion of the
bypass hose. The flow of water is always pressing it into place, so it
hasn't moved. It blocks most of the bypass flow, except what flows through
the 1/4 or 3/8 hole in the middle. That is enough flow to eliminate or
minimize hot spots in the engine when the thermostat is in the closed
condition and forces most of the coolant into the radiator when the
thermostat is open.
Query the list about skirted thermostats and partially blocking the bypass
hose. There are other opinions, but most people will agree with what I
have stated above. I know it sound weird, but check it out. Since your
engine and radiator are pretty clean, I'll bet this is a significant part
of your overheating problem.
One last question. Do you have the radiator shroud installed? (Also, are
you using WaterWetter?)
Best regards,
Jack
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