Ford Escort - Overheating engine

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Wed 28 Jul 2021 21:01
Ford Escort - Overheating engine - Alfred Rees-Glinos

(1.6 16v Zetec Silver Top engine)

Hi. The engine on my car has always run hot since I got it, (unless I keep the heater on). Although this could be a faulty temperature gauge, you can smell burning when the gauge marker gets into the red and the cooling fan kicks in. A friend, who wondered whether there was a head gasket issue, recently tested two of the spark plugs (before his tool then packed in), and the reading showed those two spark plugs to be good/not indicating possible head gasket issues.

Assuming therefore that it's not a head gasket issue, what could be the problem? One thing I've always noticed is that the coolant level never seems to drop. Could this be behind my engine heating problem? Many thanks. Alfie.

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Wed 28 Jul 2021 21:40
Ford Escort - Overheating engine - elekie&a/c doctor
It’s possible that the temp gauge sender is faulty , giving an incorrect reading . If the coolant is not boiling in the expansion tank , then the engine is probably not overheating.
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Wed 28 Jul 2021 23:53
Ford Escort - Overheating engine - Alfred Rees-Glinos

There are usually bubbles in the coolant tank actually, eek!

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Thu 29 Jul 2021 00:26
Ford Escort - Overheating engine - Fiesta1234

Is it slight bubbling or a ferocious type of bubbling that you have? I have noticed that on fiesta expansion tanks there is a slight bubbling on the return hose side and where the vapour hose goes into the expansion tank. This is apparantely absolutely normal according too ford. Try swapping out the sensor if it's easy enough and go from there.

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Thu 29 Jul 2021 02:56
Ford Escort - Overheating engine - edlithgow

How would testing spark plugs detect head gasket failure?

Can't think of anything likely to be available to the punter, though I vaguely remember subtle electrical measurements detecting knocking etc in an RnD context.

Possibly a compression test or leakdown test was meant, though a HG problem would have to be severe to show up.

The usual test is for exhaust gas (CO?) in the radiator. You should also look for coolant ("mayonnaise") in your oil.

An air pocket MIGHT also explain your symptoms, and they can be hard to eliminate. I have to boil the coolant to get rid of air pockets on my car, but I'm not advising you to do that.

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Thu 29 Jul 2021 10:07
Ford Escort - Overheating engine - Andrew-T

How would testing spark plugs detect head gasket failure?

Perhaps the OP implied studying the appearance of the plugs ?

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Thu 29 Jul 2021 10:47
Ford Escort - Overheating engine - Railroad.

Is the radiator cold when the engine is hot? If it is you have a clear problem. The radiator should be slightly cooler at the bottom than it is at the top as it gives off heat to the outside air. Replace your thermostat now in any event. If the engine overheats the wax in the thermostat will become runny and lost. Sometimes you can see blobs of wax floating on top of the coolant. In actual fact the thermostat is the most likely problem.

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Thu 29 Jul 2021 16:09
Ford Escort - Overheating engine - edlithgow

You can test a thermostat in a pan of hot water. If you use a thermometer you can check the operating temperature

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Thu 29 Jul 2021 16:52
Ford Escort - Overheating engine - Railroad.

You can test a thermostat in a pan of hot water. If you use a thermometer you can check the operating temperature

Yes you can, but I wouldn't bother. For the cost of a new one it isn't worth it. Besides, if it's lost some wax it'll open too late and close too early. This'll mean the engine will always tend to run hot. By all means test the old one in a saucepan if you are curious, but as I said earlier you should always renew the thermostat if the engine has ever overheated.

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Fri 30 Jul 2021 04:24
Ford Escort - Overheating engine - edlithgow

You can test a thermostat in a pan of hot water. If you use a thermometer you can check the operating temperature

Yes you can, but I wouldn't bother. For the cost of a new one it isn't worth it. Besides, if it's lost some wax it'll open too late and close too early. This'll mean the engine will always tend to run hot. By all means test the old one in a saucepan if you are curious, but as I said earlier you should always renew the thermostat if the engine has ever overheated.

If I test something as easy to replace as a thermostat, and it works to spec, I'm going to be reluctant to replace it, cheap or not.

I suppose you don't reproduce the operating pressure in the cooling system, so there is a possibilty that a bench test is innacurate, though its a bit of a stretch.

You can (sometimes) get different spec thermostats, so if replacing it might be possible to get one that opens at a slightly lower temperature.

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Fri 30 Jul 2021 08:23
Ford Escort - Overheating engine - Railroad.

You can test a thermostat in a pan of hot water. If you use a thermometer you can check the operating temperature

Yes you can, but I wouldn't bother. For the cost of a new one it isn't worth it. Besides, if it's lost some wax it'll open too late and close too early. This'll mean the engine will always tend to run hot. By all means test the old one in a saucepan if you are curious, but as I said earlier you should always renew the thermostat if the engine has ever overheated.

If I test something as easy to replace as a thermostat, and it works to spec, I'm going to be reluctant to replace it, cheap or not.

I suppose you don't reproduce the operating pressure in the cooling system, so there is a possibilty that a bench test is innacurate, though its a bit of a stretch.

You can (sometimes) get different spec thermostats, so if replacing it might be possible to get one that opens at a slightly lower temperature.

I'm not with you on that one. I was an AA Patrol for 12 years, and I honestly couldn't tell you how many vehicles I've attended at the roadside for engine overheating other than it's a big number. Seeing broken down vehicles first hand gives you an insight that garage technicians don't get. They only see the after effect and they make their diagnosis on that basis. Working as a Roadside Patrol is a totally different job to a garage technician, and you see everything differently and more clearly.

I used to find that the thermostat was the most common cause of overheating by far. As a temporary repair I used to jam them open (essential with a two stage thermostat). I would then pressure test the system again whilst it's warming up. On a cold day I could rarely get the engine warm enough to bring in the cooling fan, especially if the radiator was in good condition. On a hot day it was a different matter, but as long as the fan did cut it and was drawing heat away from the radiator I knew it was going to be OK.

Blocked, corroded, damaged and leaking radiators were another common cause of overheating. But even then if I could get it safe for the member to continue I would always write on the form advising the thermostat be replaced.

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Thu 29 Jul 2021 16:02
Ford Escort - Overheating engine - edlithgow

How would testing spark plugs detect head gasket failure?

Perhaps the OP implied studying the appearance of the plugs ?

How would testing spark plugs detect head gasket failure?

Perhaps the OP implied studying the appearance of the plugs ?

"Tested two before his tool packed in" suggests some gizmo, unless he broke his plug spanner.

If this was an American forum he might be using an impact wrench to remove his plugs. but thankfully it isny.

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Thu 29 Jul 2021 22:06
Ford Escort - Overheating engine - Big John

(1.6 16v Zetec Silver Top engine)

Hi. The engine on my car has always run hot since I got it, (unless I keep the heater on).

Think the keeping the heater on holding the temperature is a clue - the heater matrix is minute compared to the main cooling radiator and is plumbed before the thermostat. Therefore something is impeding cooling be it thermostat (change anyway - it's cheap) or possibly the radiator, when hot feel temperature over the whole core. Any Escort is getting on a bit so it's possible for the core to be partially blocked especially if the car has had previous engine problems / leaks(especially if rad seal has been used!).

I had a similar problem years ago with a Datsun (turning heater on to cool!) - in the end I got fed up and just changed everything re cooling except the clearly working and hard to do heater matrix, When I had everything removed the fault became clear - a previous owner had bodged a rad leak with filler paste at the front, not visible from the engine bay.

Edited by Big John on 29/07/2021 at 22:18

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