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water temp
ianminki - 12/11/17 at 01:54 PM

hi all
need some advice on water temp with a x flow it's a 1600 with bike carbs . my problem is regarding the water temp as it seams to be running hot . the rad is from a vw polo and have a header tank fitted .to be honest I am not convinced that I have plumbed in the items right ie top hose to top of rad and bottom hose from pump to bottom of rad . header tank big outlet t to bottom hose .there is a small outlet from rad to which I have put that to the small one on the header tank . fan is electric and comes on at 85c but takes a long time to off . I haven't been out on the road yet as I don't want to run if not right . its cost me a bit of money to get sorted . if anybody has any photos of x flow plumbing or there is something I have not right any help would be grate thanks regards ian

rusty nuts - 12/11/17 at 02:06 PM

X flow engines have a heater connection coming off of the inlet manifold which goes through the heater and returns to the engine at the screw in elbow at the water pump. The outlet is at the highest point of the cooling system and allows coolant to flow before the thermostat opens thus bleeding any air from the system . Do you have a heater or bypass hose? If it's blocked off that may be your problem? When I converted to TBs I installed a bleed point in the heater hose that allows me to bleed air from the system easily , just used a pluming fitting.

CosKev3 - 12/11/17 at 02:41 PM

85 is quite a low temp for an electric fan to come on IMO.

90 is the normal running temp on the majority of engines (bikes are higher) I would say coming on should be circa 95?

mcramsay - 12/11/17 at 03:02 PM

What type of electric fan are you using? And is it wired up to spin in the correct direction? Should blow through the rad if fitted to the front, or pull through if fitted on the engine side of the rad.

The reason I ask the make as the cheap £20 quid ones on eBay wouldn’t blow the skin off a rice pudding. I use a comex which easily moves double the amount of air compared to an eBay special for the same size of fan

ianminki - 12/11/17 at 04:32 PM

thanks for replies

the fan is a 12inch from cbs and fitted to front of rad . and there is no heater fitted to the car so blanked of
and header tank as high up as far as I can get it as not to foul the front end (flip front end)the car is a stylus . ran fine with bike engine in .just not sure of how it as to be plumbed in without heater fitted .regards ian

mcramsay - 12/11/17 at 04:50 PM

The cbs 12 “ fan has an output of 780cfm... the Comex equivalent is 1300 cfm.

rusty nuts - 12/11/17 at 05:40 PM

Originally posted by ianminki
thanks for replies

.just not sure of how it as to be plumbed in without heater fitted .regards ian

I think it's fairly common to run a hose from the inlet manifold to the water pump on Xflows

steve m - 13/11/17 at 08:14 AM

.just not sure of how it as to be plumbed in without heater fitted .regards ian

I think it's fairly common to run a hose from the inlet manifold to the water pump on Xflows

I run a 1660 xflow, and the fan rarely comes on, even by leaving the car running on the drive, it would take about 30 mins to switch the fan on, I also have a warning light on the dash, and an override switch to put the fan on

My setup is a polo rad, standing as upright as possible
top hose from the thermostat goes to the top hose of the rad
water pump hose to the bottom hose on the rad
water pump heater outlet goes to the inlet manifold directly
a cheap 12"fan on the back of the rad, sucking air through

have you renewed the thermostat ? as old ones do stick closed


ianminki - 13/11/17 at 11:48 AM

hi steve

yes have just got a new thermostat . one problem I have found is I had fan turning in the wrong way , only difference I can make out is the small hose from rad to a header tank and the 13mm hose to a t on the bottom hose to rad as the inlet manifold is blocked (on outlet on manifold)I am running bike cabs . I will be looking at timing as well to make sure I have that right . thanks for your reply
regards ian

JMW - 13/11/17 at 12:56 PM

I had the same system as the O/P except that I didn't use the small outlet at the top of the radiator, i.e. blanked it off, and instead ran a small tube from the housing above the thermostat to the small inlet on the tank. The thinking being that that housing was the highest part of the system apart from the tank itself, so it self bled.