shove a hose pipe in it.

Can i flush my radiator by just whipping it out and shoving a hose pipe and/or pressure washer in it?

Definitely not a pressure washer, unless you fancy screwing up the cores. A hosepipe running gently is fine. It's best to flush it backwards, i.e. from the bottom hose fitting. Is there a reason you need to flush it? If not, it's best to leave well alone.

general overheating problem solving the free way. Taken out stat and bled, generally runs fine but begins to overheat especially under load. pumps fine, i know the fan isnt at its best but its bloddy freezing at the moment i can tackle that next.
surely gently running water is what its used to? how would this help to flush?

dannybays78 said:

general overheating problem solving the free way. Taken out stat and bled, generally runs fine but begins to overheat especially under load. pumps fine, i know the fan isnt at its best but its bloddy freezing at the moment i can tackle that next.
surely gently running water is what its used to? how would this help to flush?

Click to expand...

The RAD will stand at a guess around 20psi. Reverse flushing with a hose is fine, fix the hose to the outlet, tap full on and shake the RAD vigerously with the water running and see what comes out. No guarantee it will clear blocked cores though.

What about a citric flush, may be worth a try.
Davie

total waste of time... just replace it.

couldnt get the bottom two bolts undone so did a bit of a flush in-situ, which was semi successful. Did manage to fix leak from stat housing, which had previously been siliconed, no o-ring in sight ('mechanic who i PAID to replace stat, just took it out and gummed up behind him) I suspect that leak will not have been doing the overheating problem any good.
Bizarrly though, my fan generally runs a bit slower than you would expect, but half way through the evening, whilst bleeding it was going like the clappers, stopped and re started the engine and it went back to its slow running?!
Anyway, new (or at least properly flushed) rad, a vacuum fill and i think things might return to normal. Oh and a new exhaust, but not this month!
At least my wife is getting to watch her ****e on the telly while im busy tinkering.

dannybays78 said:

general overheating problem solving the free way. Taken out stat and bled, generally runs fine but begins to overheat especially under load. pumps fine, i know the fan isnt at its best but its bloddy freezing at the moment i can tackle that next.
surely gently running water is what its used to? how would this help to flush?

Click to expand...

The idea of reverse flushing the rad is that anything stuck in it tends to be in the top of the cores. Pushing it the other way often dislodges the crap and washes it out.

I didn't make myself very clear, when I said gently running water, I really meant at much less pressure than a jet washer. A hose at relatively lower pressure is fine and often does the job. Adding some radflush or similar before flushing might help too.

Regarding your fan, I take it you've an electric variable or cycling fan which is designed to run at a speed to suit the engine temp. It's controlled by a thermostatic switch or possibly by the ECU (You didn't say what engine it is). If it's cold, the fan may stop all together or run very slow. As the engine gets hot, it'll run at a higher speed until it cools again. You may very often hear the fan "cutting in" as you're driving and sometimes the fan runs very fast for a short time after shutting off the engine.

garfie said:

Regarding your fan, I take it you've an electric variable or cycling fan which is designed to run at a speed to suit the engine temp. It's controlled by a thermostatic switch or possibly by the ECU (You didn't say what engine it is). If it's cold, the fan may stop all together or run very slow. As the engine gets hot, it'll run at a higher speed until it cools again. You may very often hear the fan "cutting in" as you're driving and sometimes the fan runs very fast for a short time after shutting off the engine.

Click to expand...

Unless it has been retro fitted with Kenlowes or a mod has been carried out to use the A/C fans....

The fan is engine driven through a Viscous Coupling...which when the engine is cold, the fan VC slips and the fan speed is related to engine speed to much....when the engine is warm, the VC starts to lock up, and the fan turns faster to pull more air through the rad....

Saint.V8 said:

Unless it has been retro fitted with Kenlowes or a mod has been carried out to use the A/C fans....

The fan is engine driven through a Viscous Coupling...which when the engine is cold, the fan VC slips and the fan speed is related to engine speed to much....when the engine is warm, the VC starts to lock up, and the fan turns faster to pull more air through the rad....

Click to expand...

Well this is the very bizarre thing... It's a viscous fan (2.5 dt) and has always run at the same speed with the engine idling. On this one occasion however, with the engine idling as normal, the fan was running at about twice the speed!? Turn off, turn straight back on... fan back to normal! Cannot understand why. Anyway, I've gone off on a tangent.
Cheers for advice, all well in the temp department today so far anyway!

dannybays78 said:

Well this is the very bizarre thing... It's a viscous fan (2.5 dt) and has always run at the same speed with the engine idling. On this one occasion however, with the engine idling as normal, the fan was running at about twice the speed!? Turn off, turn straight back on... fan back to normal! Cannot understand why. Anyway, I've gone off on a tangent.
Cheers for advice, all well in the temp department today so far anyway!

Click to expand...

At first when started rom cold, the fluid inside the VC is a little thicker and will for the first few moments act as if hot and be locked up...until the fluid warms up a tad and starts to act normally i.e. slipping...when it warms up more it then starts to lock up again to spin the fan faster....

This can be heard with a noticable difference in fan noise...