Rover 200 & 400 Owners Club

Ok so common problem - overheating

Solution - there is a ball-bearing used as a one way valve built into the inlet manifold where the pipe is for the return to the expansion tank - its only purpose is to aid warmup of the engine from cold. when the engine gets to temperature the pressure moves the ball-bearing and allows water to pass back to the expansion tank. this ball-bearing over time gets clogged up and sticks in place preventing the water to circulate when it gets to temperature.

first drain the coolant by removing the bottom hose from the radiator. then you need to remove the manifold you will see the offending design flaw on the left hand side. then using some rags clogg up the ports on the head and the manifold to prevent any of the swarf entering the engine. use a 3mm drill bit to drill out the area retaining the ball bearing. this will allow the ball bearing to drop out. use a 4mm drill bit and carefully drill right through the pipe to increase the internal diameter. bolt it all back together refill and bleed the coolant system with the heaters fully switched on and engine running.

Happy days no more overheating issues.

note: probably a good idea to flush out the expansion tank and radiator and the internal heater matrix (2 pipes that go through the firewall) using a hose pipe. remove both pipes and run a hose pipe through it till water comes out of the other one clean.

Neat fix !

Do you notice any change in warm-up times ? One of the K-series plus points was the small coolant capacity which should help this anyway.

Isn't that called the jiggle valve?

Oh I hope it is !

not really noticed any diffrence in warm up times only did the fix a couple of days ago but have lashed the car around doing a few hundred miles to check it motorway and around town long runs etc... and had no issuses at all

Jiggly valve - i was working on the assumption that i was called the "killer of k-series engines valve" *laughs*

Is that not there to assist the cooling system in removing air in the system? Fair play on removing it, but something to be aware of?

Also heard of folks drilling a small (a few mm's) in upper area of the thermostat disk as well as removing the valve - to achieve the same fix...

1234dist wrote:Isn't that called the jiggle valve?

It is indeed a jiggle valve. Probably because the ball joggles about - which doesn't sound any better.

i'm pretty sure that removal will do no harm.

I was advised to drill it out by a Rover specialist in Rochdale who worked as a Rover main dealer mechanic for over 20 years he told me that they always removed them.

I have noticed that since the fix i was starting to loose coolant tho and took it in to have it pressure tested, this didn't show any obvious leeks and wasn't dropping coolant - the mechanic said the head gasket was failing :( rather than me having to source a replacement head as mine had already been skimmed by the previous owner he used a chemical called irontite - yeah its similar to radweld or k-seal but its designed for HGF (he told me that this is what they used in the dealership with some of the ones where they were beginning to fail) they flushed the cooling system and cleaned it all out used the additive and then left it to stand for a day to allow the chemical to go off. when we put the new coolant in and fired it up we found the leak had been on the water pump... so £150 later with new water pump and cam belt i have put nearly 2k on the clock and not once had to top up the coolant - hopefully this will be the last of that problem!

ok so you havent needed to do the head gasket then? Thats good.

nah just done birmingham and back (seen loads of tourers, R8's etc... down there) still no sign of loosing coolant even after being stuck in a traffic jam not moving for over half hour