What causes this?

Isambard

Ford Capri 1.6 auto (pinto)

twice now when idling after a few miles the temp gauge has gone right up and some coolant has boiled over. What would cause that?

I suspect there is no thermostat fitted, water surging in top of rad when cold would indicate that , or that it's stuck. Maybe a previous owner had the same trouble and removed it.

Before I open it up to check, is there anything else I should look for? Faulty pump maybe. Radiator recently flushed and has new coolant in it.

scannerd

think your looking at failing pump, failed thermostat (sticking closed) or a blockage somewhere, or it could just be air-locked, have your followed the bleeding procedure?

i don't see how having no stat could cause it.

given the costs vs what damage could be done i would do the pump and stat if you don't know how old they are.

Isambard

Pump seems to be working to some extent at least and I've just flushed it. Never heard of a bleed being needed on a pinto, I've never done it in many years of Fords, so I think I'm on the right track with the thermostat which is on order anyway, so I'll start there. Thanks,

Stoolbend

Does the fan engage?

Have these a viscous coupling?

Isambard

no fixed fan. (but thanks for a good suggestion)

Muckie

Had a similar issue years ago on a Cortina, have you flushed out the engine block as well or just the radiator, could be a blocked inside.

Isambard

yes, hose piped

Nekarsulm

Sticking thermostat, or, and this is a long shot, is the fan fitted the right way around?

Edit: probably not relevant, but had a tractor that started doing what you describe, and it turned out that the water pump had a plastic impeller, which had started to spin in the shaft and not circulate the water.

Isambard

there's no thermostat, new one being fitted. Not sure if this could be the problem. I will look at the fan.

Isambard

my thermostat housing...what's the capped off pipe for? Would it be for bleeding the system perhaps?

jca

Fitting a new thermostat will probably make it worse I'd say it was removed to mask the problem. How does the heater perform in general, is it good? Does the heater stop working during these boiling episodes? Next step for me would be to remove the water pump and see what condition it's in. It's years since I looked at a pinto engine I can't remember what that blanked off stub is for, they never needed to be bled. Barring a knackered water pump I think the head gasket is blown between a cylinder and a water passage or the head is cracked.

crosstownk

Interesting problem.

I'd be inclined to agree with a previous poster in that fitting a thermostat may aggravate the problem. If it were me (and I'm no Ford expert), I'd start by pressurising the cooling system and see if it holds. If it does hold water (see what I did there) then I'd be strongly suspicious of the pump.

Isambard

I'm going to replace (fit) a thermostat and see what happens. The pump seems to be working strongly although I guess it could be intermittent. Head gasket is new. A Pump is a cheap item so will be my next port of call. Just changed coolant so reluctant to drain again if I can help it.

Car seems to have lacked in maintenance and I'm slowly correcting that.

crosstownk

Isambard wrote: »

Just changed coolant so reluctant to drain again if I can help it.

Just use water until you've solved the problem rather than waste and dispose/collect and reuse coolant.

dooroy

If you find there is no thermostat fitted then I would suspect , as said above, that it was removed in an attempt to solve/mask an overheating problem.
You may find the centre has been removed from the thermostat as ,in some cases , the outer part of the stat is necessary for sealing .
As regards the pump check carefully that the impeller is firmly attached to the shaft - it may be OK when cold for example but begins to slip when hot and not do its job.
If you find there is no thermostat then you have a more serious problem - cracked head , failed HG etc . I know you said the rad was flushed but if a rad sealer had been added at some stage there could be blocked pipes in the rad. Does it only overheat when not moving - and therefore no/reduced airflow through rad ?
The rad sealers often cause more problems than they solve - I removed heads from cars to find the small holes in the HG to allow coolant flow from head to block were all blocked with rad sealer.

Isambard

it's only overheated twice, both after a drive of 15 miles or so and at idle. First time a small amount of coolant was lost and the second time, simply the temperature gauge went up with no loss as far as I could see. I suppose the wrongly rated rad cap could be fitted, i'll get one of them too

I'm going to replace the thermostat and evaluate it then. (waiting for a securing clip which is on order) . The gauge should give a better reading then that I can monitor.

dooroy

Just a thought - I had Cortinas many moons ago and some had a very small fan which did very little for the airflow meaning the temp began to climb once the car stopped moving.
As I said earlier the fact that the overheating happened while stationary could have something to do with the airflow - poor fan or partially blocked rad which can cope if it has a good airflow through it.
How does the fan look - or can you compare it with another one from pics etc ?
Is the radiator matrix clear for the air to flow through ?

Isambard

I appreciate all the comments, thanks everyone.

Fan is standard fixed item, rad is in good condition I don't think it's obstructed at all.

Rad cap doesn't look great and is hard to remove, so could have been a replacement off an old tractor or something, so I've ordered a new one anyway. Might not help but no harm doing.

Once I get the thermostat in I'll know more, will be a week or so as I waiting on the securing clip which obviously was missing along with the Thermostat

Isambard

I've just had a quick look and noticed that the fan and it's pulley can be turned by hand with no difficulty although the fanbelt itself appears tight (usual measure would be to twist the belt through 90 degrees). I'll tighten that up a bit, could be another straw to grasp.

Also spotted the cambelt tensioner has been assembled incorrectly, nothing to do with my problem I think but good to spot!

jca

No, the way to check the tension of the fan belt is by measuring how much it deflects under firm pressure in the centre of the longest run, it should only depress by about 10mm. If you can slip the fan blades around like that it's definitely too slack, might be no harm to replace it as I'd say it's glazed from slipping.

bonzodog2

Might it have a viscous fan? These would turn easily even with good belt tension.

Isambard

no it's a fixed fan. Belt seems too slack, might be the problem I guess, but it's hard to see it stopping turning once it gets going.

dooroy

The 90 deg used to be recommended for timing belts I think .
I presume you have a V belt , not a flat ribbed belt.
Back in the day I often had problems with VWs where a V belt , after a period of use , would ' bottom out' in the pulleys and then provide little or no drive.
As said above if the belt has been slipping for a while it could have become glazed and will slip no matter how tight. A slipping belt usually squeals for a bit after starting etc but if well glazed may not.
Are there many blades on the fan ?

Isambard

the belts (twin belts) are quite new the whole car only did 38000 miles and was converted to power steering recently in mileage terms.

dooroy

Never came across twin belts on a 1.6 - only seen them on a 2.8. Maybe pulleys were changed to help drive the power steering .
What year is the car ?

Isambard

as I said, it was converted by the previous owner. pas on a 1.6 would have been rare or nonexistant from the factory

Oops!

Have you had the radiator out and give it a good check? maby half blocked...

Isambard

it's not that (but thanks anyway

jca

Ok. Where is the double pulley, the crankshaft or the water pump? Can you tighten the waterpump/alternator belt to stop it slipping? I'm assuming the power steering pump belt can be tightened separately. Are both belts in proper alignment? How is the heater( the best indicator of circulation)?

Isambard

update. Took off the timing belt cover to get easier access to the thermostat cover and the pillar that it bolts into and retains the tensioner spring came away with it. So I had to reassemble all that and then check the timing. All back to square one and awaiting delivery of the clip that holds in the thermostat. Possibly may be here tomorrow
Makes Ben Hur seem like an epic...

jca

Isambard wrote: »

update. Took off the timing belt cover to get easier access to the thermostat cover and the pillar that it bolts into and retains the tensioner spring came away with it. So I had to reassemble all that and then check the timing. All back to square one and awaiting delivery of the clip that holds in the thermostat. Possibly may be here tomorrow
Makes Ben Hur seem like an epic...

A drop of loctite will stop that happening again. Did you try tightening the fan belt?

Isambard

awaiting the clip before I can say whether it helped.

_Brian

Few things spring to mind.

Fitting the thermostat until this is sorted is a bad idea as it will compound the problem increasing the risk to toasting the engine.

Tightening the belt much at this stage could well lead to bearing failure in water pump, ive seen older pumps fail within a week of the belt being tightened. It could be the problem, but keep a tight eye on the pump.

Has the air flow through the rad been looked at ??
I’d remove the rad and blow through with air, back to front only.

Good flushing of the coolant system is required to ensure no blockages, older rads tend to gunge up if sitting about allot.

jca

_Brian wrote: »

Few things spring to mind.

Fitting the thermostat until this is sorted is a bad idea as it will compound the problem increasing the risk to toasting the engine.

Tightening the belt much at this stage could well lead to bearing failure in water pump, ive seen older pumps fail within a week of the belt being tightened. It could be the problem, but keep a tight eye on the pump.

Has the air flow through the rad been looked at ??
I’d remove the rad and blow through with air, back to front only.

Good flushing of the coolant system is required to ensure no blockages, older rads tend to gunge up if sitting about allot.

All these points have been answered already by the op, system flushed etc. If the fan blades can be slipped around the way the op describes the belt is too slack. I told him the correct tension that's required on the belt. @op, maybe I missed it but what's the heater performance like?

Isambard

car is dismantled still, I can't tell you.

dooroy

I would be very surprised if the new thermostat improved things - as some have said it will probably become worse.
In the days when the cross flow and Pinto engines were common many had their thermostats removed to prevent overheating; an engine that was otherwise in good condition would barely move the needle after a drive and certainly never overheat.
The op says in post 9 that there was no thermostat - if the engine was overheating without a thermostat then fitting one will provide more restriction to coolant flow and a greater chance of overheating.
The engines generally didn't require bleeding , but if there was an airlock it would boil up in 2-3 miles.
I have seen cars which would overheat when stationary after a drive - and the reason usually was the electric fan was not working so no airflow and an engine already up to temp would quickly go into the red.

Isambard

as jca says in post 34 , we've established it's probably the fan belt being too loose, An Post tell me the clip I need is in Portlaoise, so I'll probably have it tomorrow.

jca

Isambard wrote: »

as jca says in post 34 , we've established it's probably the fan belt being too loose, An Post tell me the clip I need is in Portlaoise, so I'll probably have it tomorrow.

Well, it needs to be eliminated from your investigation. The heater is your main guide here, the cold weather will help. Any circulation problems will show straight away with cold air from the vents.... not nice.

Isambard

well, thermostat in and fanbelt tension checked, i went for a 25 mile test today, involving slow driving , idling and rocking it.....temp gauge steady at normal at all times (was zero before), heater belting it out, so I'm calling it fixed. Any recurrence, I'll change the water pump.

jca

Lovely stuff, very satisfying. All the radiator and block flushing helped too.

Isambard

need to get a timing light now as my static timing is a bit hit and miss. Anything to improve the petrol consumption!

jca

A decent carb and electronic ignition(expensive but well worth it) and you're sorted.

whizbang

it was converted by the previous owner

It could be simply the rad cap pressure seal, but:

Pound to a penny, the original coolant reservoir was not swapped with the engine. This means the system is not holding pressure. If the system is holding pressure, it will run all day in this weather without a fan.

There is some trick with the existing hoses to cure the problem, but i never knew it.

Isambard

send me the pound: running original engine and does not have a coolant reservoir..

jca

whizbang wrote: »

It could be simply the rad cap pressure seal, but:

Pound to a penny, the original coolant reservoir was not swapped with the engine. This means the system is not holding pressure. If the system is holding pressure, it will run all day in this weather without a fan.

There is some trick with the existing hoses to cure the problem, but i never knew it.

Complete and utter tripe. Regardless of any weather every engine needs a cooling fan. There's no "trick" with hoses...