Cooling Issues

[blitzman]

Write chaps answers please.

Samurai 413 engine all standard except for a webber carb, the temperature runs in the red after 10 minutes, I`ve replaced thermostat sender unit twice, two different makes just in case, thermostat changed, the first one was bust but I also tried the new one in the kettle to double check that it opened. The water pump runs quiet and is not leaking and no play on pulley. When it gets warm the top hose after the thermostat is hot, both pipes in and out of heater matrix are hot, bottom pipe from radiator is cold, if it runs with the radiator cap off I cannot see any flow, the radiator was new 7 years ago and the vehicle does 1000miles/yr and the coolant has been changed too.
On past experience I would look towards the water pump but there is no leaking or clatter and banging coming from it, at the moment I`m not fired upt to strip it down that far and thought Id ask you guys first.........

[i_am_me]

sounds like the water pump may be the problem.
either that or the rad/coolant hoses/waterways are blocked.
try taking the rad hoses off and running a hose through the rad and pipes and see if you have a flow through.
that will rule that out so its most likely the waterpump at fault
also try taking out the thermostat and running it to rule that out.

[Jordi]

Also try radiator out and fit a hose tightly to the thermostat housing and try washing the engine through not just the rad.

[donkeychomp]

Chuck in a bottle of Kseal. If that fails then do what everyone else has said!

[blitzman]

fitted new water pump and still runs hot, coolant was at water pump and bowl for thermostat so have no doubt there is no blockage anywhere, so at great expense I have ordered a coolant sender unit from main dealer, 4x the price of a spurious unit so see what happens next week when I get it fitted. Also ran engine with thermostat out and runs slightly cooler on start up but this is what I would expct and plenty of flow.

[Cyprus Geoff]

Any update?

[Pugsley]

Based on a similar situation on my Sj410 where I had flow when peering in the open radiator and no air locks, I bit the bullet and bought a new radiator - problem solved. Yes there was flow in the old one but clearly it was very restricted. Unless I've missed it, you don't say if the vehicle is static or being driven - I take it that the radiator cooling fan is working and the air flow through the radiator is unrestricted?

[twiss]

I find the best thing to do is rev it with the cap off and a tiny bit less water than full... on my 1.3 and 1.6 you could pretty much see a river of water flowing past the rad cap hole.... not just a small flow

[sharon]

I had same issues with mine, tried all sorts. Sorted it with a race car thermostat, it's set at a much lower temp so the cooling kicks in quicker. Tried the K seal and didn't make any difference.

[ScottieJ]

Kseal.........wont put that stuff near any engine of mine I would rather find and fix the problem