Thursday, February 10, 2011

Cooling System - 0 for 3 !

Firstly be warned there may be a RANTING in this post . . . . . FECKING PRIOR OWNERS / DODGY GARAGE ! Even my daughter could and does do better !

Anyway onwards.
Along with the list of initial planned maintenance is the cooling system.
As we are in the sand pit here this always has the potential to go wrong quickly and in a big way.
So routine changing of hoses is always a good plan.
After having a look under the bonnet the hoses look . . . . . Good to Iffy.

Also the temperature gauge never seems to move more than about 10C past the 'Cold' point on the gauage, never even close to 'Normal'.
So in from the UK comes :-
- Complete Silicone hose kit (much longer lasting and better flow than rubber)
- New temperature sensor (thermistor type)
- New 75C thermostat (75C is for summer / hard use)

First pull off the hoses.

Cracked and bodged up with bath sealant !
Okay just drain the system and flush with hose then fit the hoses back.

Even a modification to tidy up the top hose to the heater box.

Next the temperature sensor.
Single wire sensor which is earthed through the engine.
Its a thermistor which means that the resistance drops as it heats up.
So if the sensor plug is insulated from the body it gives a false cold.
Such as by . . . . . . TEFLON TAPE, another WTF !!!!

I know the gauge works because I shorted the cable to the engine and needle quickly went to 'H'.
So clean the threads and fit the new sensor job done.
The seal comes from a conical face on the bottom, not by using teflon !
Lastly the thermostat.
Before fitting CHECK. While the wife isn't looking heat in a pan of water on the stove.

Opens about 75-80 which is fine.

Now remove the thermostat housing and remove thermostat.
Wait. . . . remove thermostat. . . . . . WTF NO THERMOSTAT !!!

Okay fairly straight forward, fit new thermostat, including new gasket.

The old elbow had a mounting bracket for a so called smog pump.
The smog pump isn’t fitted so to tidy up, out with the hacksaw and grinder.

Bolt it all back up and fill her up.
Fire her up and wave the laser thermometer around.
After few minutes all seemed to work, as temperature came up thermostat opened followed by radiator getting hot.

All Done, this is considered to be okay / normal.

As the engine was effectively over cooling, fingers crossed nothing to badly damaged.
Just hope nothing more sinister lurking and that she now doesn't start running hot.
If so I suspect will be new water pump which is a pain as means radiator off.
Richard B.

Next . . . . . Seats bases, unless Prince of Darkness Lord Lucas strikes or I end up doing the water pump !


  1. I see the speedo is in mph only, with some dodgy kph stickers.

    Those kph stickers would never be acceptable in Blighty. Back there, the numbers on the dial have to be visible even at night.

    Just as well you're not in Blighty, then.

  2. Passed test without them !

    It's more of a hint than actually acccurate.
    - Cable is sticking.
    - Speedo internals need overhaul.
    - Glass freely rotates.

    It's already a job on the list but getting here safe / reliable is more important.

    Used to have an imported kph bike and just had a standard sticker.

  3. Hi! I am currently wrestling with my sensor. I cannot get the blasted thing out! All the "guts" have come out--the copperish looking core and the tip, but the rest is stuck and not coming out. I've busted a spanner and a pipe wrench. I've put heat on it and nothing. Not even a budge. Tell me how you got it out!



  4. Sorry Todd.
    Mine thankfully came out fairly easily.

    You have used heat, but how much heat ? but you will need to be carefull not to fry any gaskets. If you can use a lot of heat safely then try the candle wax trick.

    Have you had a look from the inside via the thermostat housing ?

    Do you have access to an impact gun ?

    If it is really mangled you might have to drill it out, but that will be a pain.

    There are some pictures of the sensor out here.

    Richard B.

  5. I see the post is a couple of years old. Have same problem I am about to tackle. Good article with great pictures, Thanks.

    Phil F