X Flow running too hot (on short run to check speedo calibration)
Car has small ford (new) radioator in nose, Thermostat housing from Burton with filler cap and fan switch sensor. This is the highest point in the system, no header tank fitted (yet ?). The engine is running fine for a short run then overheats, it is loosing the water from the rad cap releif pipe in thermostat housing and then there is no water flow round rad.
Do I fit a header tank, with pressure cap and fit a non pressure cap to thermo housing or ????
Note, the engine is fine, no leaks, kenlow fan fitted, new water pump....etc

Help

Normally modrn car engines have a constant by- pass flow through the heater matrix this allow water to circulate around the block and head so warm water reaches the thermostat and allows it to open.Try drilling a single 1/8" hole in the thermostat this will allow some by-pass flow to pass around the thermostat which will make open quicker.

Also I take it you have two raddiator pressure caps --- not a good idea as it allows an air lock to form as air is drawn in the system cools (a rad cap has two valves -- pressure and vacum relief), try blanking off the one on the raddiator,

Also check the iginition timing -- nothing will make an engine boil quicker than excessively retarded timing.

You should have an overflow tank as a minimum - this takes the water lost from expansion and holds it until it's sucked back when the engine cools.

I agree about the rad caps - put a blanking cap on the place where you don't have the overflow bottle connected.

David

Thanks guys, but, the origional X Flow had a heater valve which when closed, was closed. (My heater circuit is blanked off, i.e. no heater.
I only have one pressure cap, it is on the Thermostat housing as described above, the rad cap is a totally sealled one.
Timing is ok.
Question is, when I fit an expansion bottle, do I have a blanked cap on thermo housing and pressure cap on expansion bottle.
Wish I could do those nice computer drawings that some on this site can do to show what I have and or what I need. Any body out there that can do this ??

quote:

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Originally posted by Fifer
Question is, when I fit an expansion bottle, do I have a blanked cap on thermo housing and pressure cap on expansion bottle.
Wish I could do those nice computer drawings that some on this site can do to show what I have and or what I need. Any body out there that can do this ??

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May be worth running hose from inlet manifold heater outlet to water pump union , may help ,also take off thermostat and housing when filling system until waterways are full then refit stat , stops any chance of air lock. check for head gasket failure. if all else fails try Red Line Water Wetter?? willreduce temperature by 15-20 degrees. Rusty

Hi, may sound obvious- but is the thermostat the right way round??
Yes I can cough to fitting mine the wrong way round!!!!, gave the same problems you describe- and yes I felt a complete tool!! dunno how it happened!
regards,
Greg

Just to clarify, which end of the thermostat should be pointing into the block?

Same even with thermostat removed, I also have a valve between the inlet manifold out and wtr p/p in and tried it open, and closed.
Still would like to know, do you fit the pressure cap on expansion bottle and then fit blank cap where existing one is on thermo housing ?

Thanks Dave, this is exactly what I was looking for. I will rig mine up this way too.
By the way, I found that the head gasket is gone !, I dont beleive it was the initial problem, as it probably went with the engine running too hot to start with as it was running fine for weeks while I was getting the engine set up etc and the carbs fitted etc.
Thanks for the help, I'm sure this will cure it once I get the head gasket changed and fit the expansion tank.

ive done mine like that david, except ive bypassed the heater matrix, i just put a pipe between the ends. hope it works! cant test it to temperature cos i have a leaky pipe that needs swapping...

Dave that info is just what i have been looking for and well laid out .
where did you get the thermostat housing from I have the one with a rad cap/sensor and the one with just the temp sensor in but not with a vent pipe on. where did you get it from?.
does the pressureised water not come out of the vent pipe?
and lastly do you know of a suppler of rad caps that dont open?
sorry for all the qustions but now i am through the sva stage i need to get the car running right.
tfyt Barrie

The thermo housing I have is from Burtons.
The water / air can come out the vent but is connected to the expansion tank.
I cut off the sring and seal from my normal pressure cap and then soldered up the rivet in the top.

Cheers fifer i will try all this this weekend did the rad cap mod work under pressure?,because i,ll have to do it to two caps (thermo,and raditator)
tfyt
Barrie

You can get dummy caps quite cheaply from most motor factors - put this in the 'non-active' location.

rgds,

David

Removing the spring etc from the cap and soldering up the rivet in the top worked fine, no leaks. I had to do both my caps also (rad and thermo housing)
I fitted an expansion tank off a volvo 7 series and it works great and looks pretty good too