Conference terri::cars_uk

    
    In a Kent X-flow (1700) I've been having trouble with the cooling
    system - has anyone got any pointers as to what to check.
    
    Symptoms:
    
    Runs at normal temperature (~70�-80�) with no water loss when used
    gently.
    
    When pushed, the expansion bottle fills up and overflows (automatic
    screen wash!) and the water temperature shoots up to ~100� - this is
    when I stop and let everything cool down.  This has happend a few
    times now.
    
    Checked:
    
    The coolant system is full (bled the air out of highest point, run &
    recheck).
    The radiator cap pressure release is OK (replaced).
    There don't seem to be any obvious blockages in the system.
    The thermostat works without problems.
    There aren't any leaks noticable (apart from the expansion bottle!).
    There doesn't seem to be lots water getting into the oil (just from
    looking at the oil).
    
    Anybody got any ideas of what this could be or what to check?
    
    Thanks,
    Rob     
                                        

    
    Ah at last someone who knows a Kent isn't an Essex! :^)
    
    Is the radiator definitely free of blockages? Failing that, when you 
    say 'pushed' do you mean using high revs? Maybe the water pump and or
    pulley are not suited to your car's system.
    
    Just an idea,
    
    Mark
    

On a Mark 1 Cortina (I know, I know...) - it was a GT version that had been
"breathed on" by a Cosworth mechanic.  Wish I still had it today, though!

The problem was worn piston rings, and low compression.  When tootling around
toown, it was fine, but when pushed the blow-by from the worn rings really
heated the engine up and the rad boiled.

more thoughts ....		Brian

    Thanks for the info so far...
    
   > The problem was worn piston rings, and low compression.  When tootling
   > around toown, it was fine, but when pushed the blow-by from the worn rings
   > really heated the engine up and the rad boiled.
    
    I'll give the compression a check, but I hope the piston rings aren't
    worn as it hasn't even done 3000 miles yet!
    
    Rob

I used to have a Fiesta Mk1 1300S, and as far as I know, this had a "Kent"
engine. I used to get similar overheating problems. The compression idea
sounds quite plausible. I'm sure mine didn't run as well as it should have.

Mark.

    
    Hi,
      I had a similar problem with a MKI pre-xflow with stage 3 head. the
    problem was that where it had been rebored the sleeves were so thin
    that the when 'pushed' the the cylinders became exceptionally hot and
    the coo;ing system could not cope, eventual fix was a cortina 2000 gxl
    rad and a little front end reworking. It still ran hot, but never over
    heated. Probably not your problem, but thats my 2 peneth...
    
    
    
       Alan.
    

	The head gaskets gone. Classic symptoms.

	-John

    My 2p on overheating
    
    I had this problem, but with an Imp variant engine.
    
    First thing I did was flush the rad, and loads of crud came out so i
    ticked this off as eliminated. Went on to check everything else that
    the previous entries have suggested - all to no avail other than i got
    to know the engine pretty well.
    
    Finally changed the rad and the problem was cured completely.
    
    I'd suggest that you try and check the actual capacity of the rad
    against what it should be and see if it indicated and blocked 'veins'.
    Flushing clears the loose crud, but won't clear the blockages.
    
    
    AmS

    Don't forget to reverse flush the rad.... in 9 cases out of 10 that
    will get a whole posse more cr*p from the rad than flushing in the
    normal direction of flow.

    Thks for all the usefull stuff.
    
    I'll be taking the cooling system apart and give it a clean out - it's
    due for one.  I had a word with a friendly mechanic at the Caterham
    works who said that it sounded like a cracked bore which only opened up
    when using a lot of right foot - pressurising the coolant.  Another
    possibility is that its a head gasket - either way a normal compression
    test might not show the problem.
    
    Has anyone done any high pressure tests to check this kind of problem,
    what sort of pressure is needed to show up a hole into the coolant?
    
    Rob
    
    PS - The coolant system is the same as many others using the same and
    larger engines engine - and there isn't any more room to do anything
    about it anyway!                                     

    
    The Marcos has similar problems to Rob's Caterham. Fine for a while,
    but the water is disappearing somewhere (A mystery. It's not in the
    oil or the cylinders as far as I can tell and there's no sign of a leak
    in the engine bay. The only water I've ever seen leaking out is from
    the radiator overflow), and then the car gets hot.
    
    The car never used to have any problems like this until I had
    the radiator neck repaired (there was a split). I can't say this
    problem started directly after that, but it wasn't there before.
    
    Rob mentioned changing his radiator cap. Is this a worthwhile exercise?
    How could the radiator cap be causing the water to disappear (it's not
    coming out around the cap)? My guess is that something is pressurising
    the system and causing the water to be forced out of the radiator
    overflow. Is this possible/likely?
    
    Mark

    Hi Mark - my comiserations, this sort of thing nver happens when the
    weather's bad...
    
    The reason I 1st changed the rad.cap is that the pressure release to
    the overflow/expansion tank is controlled by the sprung rubber-lined
    piece which forms one of two seals to the radiator.  I though that the
    sping may have "worn out" or the rubber not sealing properly allowing
    very low pressure to fill and overflow the expansion tank.  This wasn't
    the problem.  On your car it could be one (or more!) of two things -
    either the head gasket is leaking between a cylinder and the water
    jacket, or there is some other hole/crack etc in the engine.  Either of
    these will let the high pressures of combustion into the water system
    and overflowing it.  On my car this only happened when I was
    giving-it-a-bit-of-righ-foot, but would be fine when tootling along
    quietly (sensible mode).
    
    I hope for your sake it's only a cheap gasket - is your engine
    overbored?  If not then the gasket is the more likely culprit.
    
    Rob

    
    Thanks Rob,
    
    I don't know if my engine is overbored (3.1 Essexs are fairly common),
    but there is a possibilities that the rad cap is the offender since the
    problem has appeared since the leak in the rad neck has been repaired.
    Obviously there is a possibility that the water leaking through the 
    neck was stopping the leak at the rad cap, but it could also be a
    problem with the head gasket as you describe, or maybe a more expensive 
    problem (although the problem doesn't seem to be speed related, more
    time related as if the water loss is continuous).
    
    I'll get a new rad cap at lunchtime.
    
    Mark

    
    Thanks too, to you Derek, for your suggestion. That would fit with the
    'new' radiator causing the problem.
    
    Mark
    
    PS Have you had any experience at fixing fibreglass cracks?

    Are you allowed to dump radiator contents onto the track?(!)  Or are
    you only allowed to use water in the radiator without lots of slippery
    additaves (Austrian wine included).  I guess the only antifreeze you
    need is the driver (if its cold enough for antifreeze, then it's too
    cold to drive)       
    
    Rob

>Radiator contents yes oil no.
> The water comes out when you slow down afterwards and the temperature
>climbs a bit to 98- 100c after running at 85c round the track.

They don't let us do that in the U.S. We have to have catch tanks for the
oil and water.

As far as the problem, my brother just had a problem with his Formula
Atlantic. The water was mysteriously disappearing. The car ended up
overheating during a race. He pulled right into the pits. When he told the
engine builder about the disappearing water the guy said the head gasket
failed. He said if any of the head bolts are loose the head has annealed
and softened and needs to be fixed. My brother took the cam cover off and
some of the head bolts were loose. He took the head off and the gasket was
shreaded. 

Needless to say, it was not cheap. 

     My 1991 Escort 1600 has the following "problem" with the cooling, any
    suggestions to what is causing it and how to fix it:
    Until last weekend when the car was up to temperature the needle on the
    temp guage would sit exactly half way between hot and cold, now as the
    car warms up the needle comes to the half way position and then drops
    back into the cold region ... occaisionally it returns to the half way
    point only to fall back the cold a few minutes later.
    
    Any ideas ?
    
    Martin

I agree with .33.  If you have air in the system, when that 'bubble' gets to 
the temp sensor, it will not register as hot as the coolant so the needle will 
drop.

Dave

    Does the needle - stay at mid point when car moves slowly (stopped)
    		    - fall to cold when car moves (fast) ?
    
    In the affirmative look for the thermostat.

    Intermittent electrical problem

	I've seen this on an Escort as well (old shape, 1.8 Diesel). When I 
	mentioned it at the garage, they immediately said it was the temperature 
	sensor. Indeed, everything went back to normal after it was replaced...

	FWIW,

	/Ben

    Here's a question for you all :-
    
    The situation... I've had to change the thermostat cover on my A-series
    engine from a Metro item to a Mini item. Now, the metro one had a small
    extra outlet (no more than 4mm diameter) for an 'overflow' connection
    to the header tank. The mini one does not.
    
    Hence now this overflow pipe is temporarily blocked off to/from the
    header tank.
    
    My question is, what direction of flow normally occurs here when the
    coolant expands? Is the pipe intended to carry excess coolant from
    thermostat --> header tank, or vice versa ? I imagine the former.
    
    Second question, then, is what are the side effects with leaving this
    blocked for the moment?
    
    Cheers,
    Dan
    
    P.S. Anyone know where I can find a T-piece which I can put in the
    large diameter radiator hose, and take off this small diameter overflow
    pipe so I effectively have the same old setup?!

    	Another use of these small diameter pipes to header tanks is to
    allow displaced air and steam to end up in the header tank, instead of
    forming a vapour lock and blocking the flow of coolant around the
    circuit. I don't know A series engines at all. Is the thermostat cover
    one of the highest points that water reaches? If it is then this is
    probably the function of the pipe. The mini may not have a header tank.
    The pressure cap is probably on the radiator, so gas will be vented out
    here. This may explain why the Metro originally had this connection and
    the Mini cover doesn't. 
    
    	I had a kit car with a radiator without a pressure cap. The header
    tank was originally connected into one of the heater pipes. This worked
    ok until the weather warmed up. After that the car would be fine until it
    heated up enough for a vapour lock to form in the top radiator pipe.
    This would block the coolant flow and the temperature gauge would hit
    the end stop. I altered the system so that the header tank connected to
    a T on the top hose. No more problems. 
    
    	hope this helps.      Jeremy

    Didn't see the PS on -.2
    	If the radiator hose inner diameter is 1 1/4" then Westfield do a
    suitable T piece to connect a 5/16" ID tube. Guess what I used to fix
    the problem described in -.1!

    Yup that's exactly what it is (right on the top hose).
    
    I'll have to re-instate it as soon as possible.... where did you get
    the T piece? Normal ones aren't much use as the top his is fairly
    large... (1�inch?) yet the vent pipe isn't big at all.
    
    It's not much of a problem at the moment (ie. cold) but in the summer I
    feel it might need it.
    
    Cheers for the fast response,
    Dan

    re.40 Beat me to it!

RE: .38
I think that the A-Series engine has this take-off point for the 
expansion bottle because on some of the cars in which this engine is 
used have the radiator mounted quite low down. In these cars the the 
thermostat housing is the highest point in the cooling system so 
bleeding air out of the system from the radiator will not work - you 
get air left in around the thermostat area. 

The water flows both ways along the small pipe to/from the expansion 
bottle - to the bottle as the engine heats up, from the bottle as it 
cools. If you replace the housing and don't use the expansion bottle 
you had better make sure you have a pressure cap somewhere else in 
the system, if you don't something is going to 'give' at some point!

- John.

    Well me and my big mouth!
    
    Driving back last night, and what happened!? Yup, it overheated with an
    air lock in the upper hose around the thermostat area.
    
    Luckily I have a drain pipe located at the front for easy bleeding of
    the system, so it was a simple case of overfilling the expansion tank
    until I got piping hot water out the front of the car..... no (serious)
    problem.
    
    Looks like I'll have to figure out a way to put that Metro thermostat
    housing on while keeping the current engine steady :-(
    
    Cheers,
    Dan

Could this problem have been something to do with the fact that you were 
attempting to tow a Metro at the time?  8-)

Helpfully....

    No. The engine should have stayed cool anyway. Even when we were moving
    (which normally means the thing cools down) there was no difference.
    The air lock meant no water was getting back to the engine.
    
    Draining the rad, there was just freezing cold water coming out!
    
    Cheers,
    Dan

    re.40
    
    Just phoned Westfield. The T-piece in question is made up for them
    specially (ally) and is just under �30.
    
    :-S Ulp!
    
    Oh well.... either that or constant overheating :-)
    
    Cheers for the pointer,
    Dan

    	The T piece also includes a theromstat switch for an electric fan,
    hence the higher than expected price. Could be useful if you don't have
    one already. 
    			Jeremy

    Ah, they didn't say that. That will be handy, yes. The existing one (in
    the radiator) has always been a bit dodgy :-)
    
    Bloomin' rover parts!
    
    Cheers,
    Dan