Vauxhall Corsa 1.4 2010

Dynamo
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He who is without oil shall throw the first Rod. See the book of Compression's 8.7.1

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Vauxhall Corsa 1.4 2010 Sept 2, 2022 20:24:56 GMT 1

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Post by Dynamo on Sept 2, 2022 20:24:56 GMT 1

Testing cooling systems.

I've got a problem with a cooling system on the twin cam variable valve timing engine setup. The customer brought it in advising that the cylinder head gasket was leaking. The cooling system was full on arrival and while running the engine I was not happy with two areas;

1/ The radiator hoses top and bottom were at significantly different temperatures when the coolant was boiling in the header tank reservoir. The cooling fan would cut in but I knew a circulation problem was present. Suspecting that the thermostat was not opening I changed it. After refilling the cooling system and running the engine I got ALL hoses hot and the heater blowing hot. The coolant didn't seem to boil in the reservoir anymore.

2/ I didn't like the feel of the reservoir cap when refitting. Something about it lingered in my mind thinking that maybe the vent is not functioning as normal but at the time seemed to be working.

The customer brought the car back the next day saying that the coolant was boiling and exiting the reservoir. I decided to put a new cap on and I ran the engine again and road tested it and all seemed fine. The next day the customer returned advising that the same happend again.

This was the time when the boss advised me to remove the lower radiator hose and collect the coolant, and then put plain water back into the cooling system, but, in his words, pour the water into the lower radiator hose and fill the cooling system thus HE thought would prevent the cooling system allowing air to enter?

At that point I said, I'm done.

Yesterday the customer rang asking about the car and I advised him that I'd carried out some tests and although two cylinders were lower on compression than the remaining two, at about 30 psi each cylinder, I didn't think they were the cause of the cooling system problem.

When the engine runs from cold to hot I never seem to see any currents in the coolant system reservoir. The breather hose never admits any coolant back into the reservoir either. As I can't seem to get the coolant to vibrate indicating that the water pump is working, I advised the customer that I thought it may be that the impellor has either broken or detached from the water pump spindle?

Looking through my old tool stock from the 1990's I've dug out an old Snap On cooling system tester and using other attachments I've managed to hook up to the WPS500x transducer. Now I'm thinking on this car that test would prove fruitless because no water currents can be seen and therefore no voltage changes would take place. Also I've no reliable data for comparisons yet, but what do you guys think about using this method for testing water pumps?

You can't "unbreak" the broken,you can only break the unbroken to break the break of the unbroken, for me, you cannot unbreak me, for I am already broken,so you have no need to break the break because I am not unbroken.

dizzydiver
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Vauxhall Corsa 1.4 2010 Sept 2, 2022 20:57:50 GMT 1 Dynamo likes this

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Post by dizzydiver on Sept 2, 2022 20:57:50 GMT 1

Have you tried a sniffer to see if the head gasket is leaking and pressurising the coolant system?
Run it from cold to hot, you never know, it might only be leaking when hot.
I must admit, I've had a few water pump vane failures over the years. Plastic on steel is never a good idea, heat and time cause brittleness.

Dynamo
MOT tester

He who is without oil shall throw the first Rod. See the book of Compression's 8.7.1

Posts: 4,302

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Last Online: Apr 29, 2017 15:36:01 GMT 1

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Vauxhall Corsa 1.4 2010 Sept 6, 2022 19:19:15 GMT 1 mike617 likes this

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Post by Dynamo on Sept 6, 2022 19:19:15 GMT 1

I checked the cooling system operation today with the above WPS500x. Pressure rising in the cooling system almost from the word go. Internal leak somwhere like headgasket, head/block? More testing required but I think the headgasket will get the blame.

You can't "unbreak" the broken,you can only break the unbroken to break the break of the unbroken, for me, you cannot unbreak me, for I am already broken,so you have no need to break the break because I am not unbroken.

Dynamo
MOT tester

He who is without oil shall throw the first Rod. See the book of Compression's 8.7.1

Posts: 4,302

Class tested: 4

Last Online: Apr 29, 2017 15:36:01 GMT 1

Likes: 1,310

Vauxhall Corsa 1.4 2010 Oct 15, 2022 22:12:25 GMT 1

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Post by Dynamo on Oct 15, 2022 22:12:25 GMT 1

Sept 6, 2022 19:19:15 GMT 1 Dynamo said:

I checked the cooling system operation today with the above WPS500x. Pressure rising in the cooling system almost from the word go. Internal leak somwhere like headgasket, head/block? More testing required but I think the headgasket will get the blame.

They customer brought the car back the other day and left it with us. I didn't notice that it was the car above. Two days ago the boss had the young lads change the thermostat again thinking maybe that the new replacement fitted previous was possibly faulty!! Yesterday the boss asked me to look again at the cooling system as the exact same problem is still occurring.

Revision from previous work..

The car came in overheating. I thought initially that the thermostat maybe was the cause because the top hose was hot but the bottom hose was cool. I also remember not liking the feel of the reservoir cap when fitted! We changed the thermostat and the same problem was still present, and then we changed the reservoir cap. The fault didn't seem to clear and then I changed the water pump and customer took the car away. I never thought the fault had been fixed and the customer took the car away. I never thought he'd of returned with it. All this occurred back in the beginning of September. At this time when the cooling system pressure seemed to rise, this has now been established as caused by a leak on the adapter used on the cooling system equipment that was used to locate the WPS500x transducer. Given the adapter is some twenty seven years old the connector I think is entitled to leak by now, which is what caused the coolant pressure to rise.

Yesterday I thought maybe the radiator could be blocked or partially blocked. The reason being that when the top hose was hot and the bottom hose was cold, the radiator core was also cold yet the cooling fan would cut in/out in operation. I removed the hoses and using a pressurised water gun I bought back in 2019 I flow tested the radiator. I didn't find anything wrong and reinstalled the hoses.

Today I was asked to look at this cooling system again. I thought, nothing to loose, get the Pico out and the WPS500x and do some testing. Having run the engine to normal operating temperature, this being when the coolant starts to boil, I then shut the engine off and removed one spark plug at a time and installed the WPS500x. Running the engine at idle for about 35 frames of data I then carried out the same tests on each of the cylinders. I found nothing wrong within the engine assembly, i.e. no leaks. I then moved onto the cooling system reservoir and using my old adapters from the 1990's I installed the WPS500x onto the cooling system reservoir. After setup I left the engine idling for about 25 frames. No changes took place as far as pressure variations occured, that was until the leak started occurring. The changes are shown as a voltage change if a fault is present, however, experience shows that varying the engine speed while temperature rises shows a variation in voltage. This must not be confused with pressure rising due to faults!

What I noticed!

The cooling system did not boil up. The cooling fan operated as normal. The top and bottom radiator hoses both became equal in temperature, and the heater hoses were hot.

What had changed then?

The only component missing from the cooling system was the reservoir cap. Given today that we had three Corsa D's in for various jobs etc, I decided to borrow a reservoir cap and fit it to this Corsa and see what happens!

Having left the engine running in the workshop the cooling system stopped misbehaving, the cooling fan cut in/out as normal. I took the car for an extended road test and no problems occurred. When I arrived back at the garage I left the engine running and visually checked the coolant level through the reservoir. The level was at the maximum. No boiling was occurring. The cooling fan cut in/out as normal.

The conclusions.

The reservoir cap, although bought brand new previously proved to be defective in operation.

Best working practice...

Don't buy none genuine OE parts.

Twice this has occurred to me now with radiator caps, the first time being back in 2019 on a Fiesta and now this Corsa. Buying none genuine parts can be both misleading and time consuming when things go wrong, and can be very costly as this case has clearly shown.

You can't "unbreak" the broken,you can only break the unbroken to break the break of the unbroken, for me, you cannot unbreak me, for I am already broken,so you have no need to break the break because I am not unbroken.

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Post by Dynamo on Sept 2, 2022 20:24:56 GMT 1

Post by dizzydiver on Sept 2, 2022 20:57:50 GMT 1

Post by Dynamo on Sept 6, 2022 19:19:15 GMT 1

Post by Dynamo on Oct 15, 2022 22:12:25 GMT 1