hot temp' gauge why ?

Post by **sidsmith** » Mon Sep 17, 2007 1:16 pm

hi moggy men, I have put a water temperature gauge into mungo ('56 splitscreen ) now what i would like to know is, should the gauge go up to the hot position when the car is idling on tickover after starting up?
with the engine running and the radiator cap off should i be able to see the water circulating ?
I know that there is no blockage in the radiator as I took the bottom hose off and the water just flew out. the gauge has been wired correctly with a new voltage regulator (stabiliser).
i'm beggining to think that if the water is not circulating properly could it be the water pump, your input would be most welcome.
mungo

Post by **Alec** » Mon Sep 17, 2007 1:56 pm

Hello Sid,

it depends what you mean by 'hot' and how quickly.
As the thermostat is closed when you first start there will be little circulation through the radiator. Shortly after you should feel the top hose get warm or hot. Your temperature gauge should start registering before that happens. You would normally need to rev the engine to see any turbulence in the radiator and only after it has warmed up.

Alec

Post by **Rob_Jennings** » Mon Sep 17, 2007 4:05 pm

question...

you are running the gauge from the 10v regulator behind the speedo? if not it will over read to full scale most of the time

Post by **Alec** » Mon Sep 17, 2007 4:15 pm

Hello Rob,

umm!, perhaps you would like to re-read Sid's post?

Allec

Post by **MoggyTech** » Mon Sep 17, 2007 7:45 pm

Quick test for water pump. Let engine warm up, feel top and bottom rad hoses (beware of the fan) bottom hose should feel cooler than the top hose. But if pump pulley is turning and the pump isn't howling, very little chance of water pump being that broken.

I take it the gauge came supplied with the sender that screws into the cylinder head? They tend to be matched, so you can't pick 'n' mix without strange results.

FWIW My electronic type temp gauge (TIM) climbs to just under 80C, then when the stat opens, it settles to about 75C and stays there.

Post by **bmcecosse** » Mon Sep 17, 2007 10:17 pm

The water pumps are uber reliable - may leak eventually - but always pump water. If your car is getting too hot - the thermostat may be stuck - and this of course will seriously block the flow and you won't see any in the rad. But idling can be confusing - take it out for a good run and see what happens then.

Post by **Axolotl** » Wed Sep 26, 2007 5:10 pm

I know that there is no blockage in the radiator as I took the bottom hose off and the water just flew out.

Er, that doesn't necessarily mean it's coming through all the radiator.

I had an overheating problem due to most of the radiator cores being blocked. Water still flowed easily through the rad, but not through the bits that do the cooling.

Also, you'll get the bottom half of a completely blocked radiator and some of the engine block liquid "falling out" when you take the bottom hose off, it doesn't mean it's clear.

I have a 1098cc unit. It gets slightly hotter if left ticking over for a long time, but not "hot".

Does the gauge show it cooling down again when you move? Does it get hotter again if you go fast for a long time? Could be a partially blocked radiator if so.

Post by **Willie** » Wed Sep 26, 2007 7:00 pm

It depends if you do actually mean that the gauge goes to 'hot' as soon as you start from cold and let it idle. If that is what you mean then no,
it should be several minutes before the gauge even starts to rise. If this is the problem then your sender unit is probably the wrong one for that gauge.