Cooling System Fault F4r

[Matt Cole]

Chaps, im having issues with the cooling system on the 225 engine. The set up i have is using a clio/19 16v rad. The inlet/outlet of this rad is the same sort of setup/orientation as the 5 gt's. I'm having trouble with the thermostat opening and the fan switch to be activated. Due to pipework issues the rad is piped up in reverse. Looking from the top the pump outlet hose( i think metal pipe at the bottom of the block same as on the 172) is piped to the right hand rad outlet. The pipe from the t stat housing is piped to the left hand inlet/outlet of the rad. Now the water in the t stat housing is red hot (over 90 deg on the lap top) but the stat wont open and the rad is cold) If i remove the stat, water circulates, the rad heats up and all is well apart from i can't get the fan switch to activate (78deg one??!!) I have tried an 86 and 89 deg one too. Rad seems to be clear with no cold spots, the t stats only open with really boiling water on them allbeit not fully open? I presume all is bled well, i bleed from the top of the rad and the stat housing. Any pointers would be great.

[Andrew Cooke]

have you got the wax bit of the stat on the hot side? You could try a small hole in the stat to allow hot water to circulate all over the stat. Finally you haven't managed to get the stat in an air pocket by any chance?

[Scoff]

the bottom pipe on the block is the inlet matt, this needs to have a straight route to the bottom of the rad. top hose on the o/s of the cylinder head is outlet. it sounds to me like the stat is dead.

[Matt Cole]

Right update from todays playing. The way i have the pipework looking from the top of the rad id the inlet pipe from the block is piped to the righthand side of the rad. This is roughly half way up/in the middle of the 16v rad. The left side of the rad is piped to the oulet on the stat housing. Could this be a bad way of piping the system up? The stat (89 deg has opened today at about 94 deg on the lap top, but this could be a small % temp error in the calibration of the sensor. The fan switch has activated too (which is a 78 deg one) Thing is i think it should cut off at about 63 deg which im not sure it will. Either way im not too happy with it and its piped up like this because of very little space. Im tempted on using the gt rad, but im not too sure how efficiently it will cool this engine?

[Matt Cole]

Andy the stat will only go in one way. I think there was an air lock which prevented the stat from opening. It now works albeit n ot very well. (see previous post)

[Scoff]

I think you mean the bottom of the block is connected to the rad port that's half way down the rad, and the top stat pipe is connected to the top of the rad. if so then thats fine.

remember that f engine will want to run a lot hotter than a gtt, 90 odd degree's is normal. sounds like your rad fan switch is a bit too low, it might want to come on a bit too often.

[Matt Cole]

Yeah sorry scoff, not easy to explain. Yes left port at bottom of rad to stat housing, right port (half way down rad ) to bottom of block inlet pipe. I was worried about the temp creeping up i did see 100deg on the lap top. It seems to balance out at around 94 deg when the 78 deg fan switch activates. This leaves me worried and confused on exactly whats going on!

[Scoff]

bottom of rad to stat housing ?

[Matt Cole]

bottom of rad to stat housing ?

Yes the lowest rad port below the fan switch(which is on the left looking from the top) piped to the stat housing. The other rad port higher up on the other side to the block inlet.

Not sure its gonna work efficiently like this??

[Scoff]

that might do some funny things. what happened to the top radiator port ? do you have it in upside down ?

the lowest port on the radiator wants to go to the block, the stat outlet wants to go to the highest.

how are you bleeding air out of the top of the radiator if it's in upside down ?

[Matt Cole]

Heres a da vinci mock up of the layout Scoff. No the rad aint upside down, this is how the 16v rad is i presume? On the top right there is a bleed screw.

[Scoff]

yeah, you want to swap the hoses over and drill/tap an end tank at the top so that you can run a pipe from the top of the rad back to the header tank, else you'll have 50% of the rad full of air.

[Matt Cole]

Ohoooo thats going to be difficult with this rad due to space. I do have a bleed from the stat housing to the top of the expansion tank. Well mate thanks again for the pointers.

[Scoff]

yes but your bleed needs to be from the top of the radiator, not the stat housing.

[Ashy]

and drill/tap an end tank at the top so that you can run a pipe from the top of the rad back to the header tank, else you'll have 50% of the rad full of air.

The 16v rad has a bleed screw at the top, its the same rad that i'm using and it works fine, but as you say Scoff mines pipped up with the T-Stat to the rhs of the rad (looking from in front of the car) and the water pump inlet to the bottom (left hand) outlet of the radiator.

THinking about it Matt its proably fine but maybe the sensor is slightly out like you say, a few % on the calibration. might make 90degrees seem like 95 which makes it look worse!!

Best bet is to plumb your temp gauge in and see what that reads to be sure!

The spare T-stat I have is 89 degrees so I guess thats the same as yours? If you find out what the thread is on the adaptor I can get a boss made and welded onto a spare T-stat housing for you to fit your gauge sensor in.

[Scoff]

yes, but ashy, his rad is upside down, no ? so where is the radiator bleed nippe now ?

[Ashy]

no its not upside down mate, its the right way up... same as mine.

[Scoff]

no its not upside down mate, its the right way up... same as mine.

ah, ok, then its fine with the bleed ofcourse.

[Scoff]

I still think the pipes want to be the other way around though.

[Matt Cole]

The 16v rad has a bleed screw at the top, its the same rad that i'm using and it works fine, but as you say Scoff mines pipped up with the T-Stat to the rhs of the rad (looking from in front of the car) and the water pump inlet to the bottom (left hand) outlet of the radiator.

THinking about it Matt its proably fine but maybe the sensor is slightly out like you say, a few % on the calibration. might make 90degrees seem like 95 which makes it look worse!!

Best bet is to plumb your temp gauge in and see what that reads to be sure!

The spare T-stat I have is 89 degrees so I guess thats the same as yours? If you find out what the thread is on the adaptor I can get a boss made and welded onto a spare T-stat housing for you to fit your gauge sensor in.

Will do me old. Good crack

[Matt Cole]

Ran it up from cold last night, got up to temp, and then pressurised the header tank!! Relesed the cap and the water level dropped down. Yep deffo something not quite right.

[Andrew Cooke]

is there a running bleed (small pipe) from the top of the rad to the header tank?

[Matt Cole]

is there a running bleed (small pipe) from the top of the rad to the header tank?

No chief, just a bleed screw at the top. There is a bleed pipe from the stat housing to the top of the tank.

[dave j gtt]

I still think the pipes want to be the other way around though.

thats what its sounding like.

[Andrew Cooke]

this any use?

[Matt Cole]

Cheers Andy. Its nice to see the pipework but it doesn't show how its connected up to the engine etc. I think there is something wrong with the flow rate too.

[Andrew Cooke]

Cheers Andy. Its nice to see the pipework but it doesn't show how its connected up to the engine etc. I think there is something wrong with the flow rate too.

I thought you'd be able to tell from the angle of the pipes, and that the water pump is on the end of one of them?

[Matt Cole]

It looks like the tank is piped to both sides on the top of the rad. The stat hose to the top port and the rad with the two branches to the heater matrix?? The u shaped pipe i have no clue on and theres a lack of turbo pipes. In all i think i may have the system completely wrong as one of the ports on the stat housing was blocked off on the f4rt but on the 172/182 it isnt and circulates to the expansion tank.

[Dave Reed]

Can't you just pop to a local renault show room and look at a 225? Just say your intersted! lol.