Vauxhall Corsa 1.4 2010

Technician · Post by **Technician** » Sat Aug 27, 2022 11:21 pm

We have at the moment a customer complaining of his engine overheating. Two days ago I spoke with him and he was advising me that the cylinder head gasket was possibly leaking! I checked the coolant level which was at the recommended maximum. I therefore ran the engine until the coolant started to boil inside the header tank. Feeling the coolant hoses at that time proved that the hose from the thermostat housing was cool and the remaining radiator hose was hot. The heater hoses were felt and only one was hot. I saw an engine warning lamp on and used the scanner to read live data and fault codes. BO087 indicating a coolant flow problem was present, and live date at that time recorded over 100 degrees coolant temperature. I advised the customer given the radiator hoses are hot and cold that maybe the thermostat is not opening correctly?

I changed the thermostat and ran the engine bleeding the system until ALL hoses were hot and the heater blew hot air out contineously. A short road test was carried out and the cooling system seemed to behave normally, however, today the car has returned, the cooling system is boiling in the header tank and the heater hoses are warm and cold again. Repeatedly priming the system today gained no positive results, the coolant boils within the header tank.

The customer advised he thought the head gasket was leaking, however, I was not convinced the head gasket was or is the cause of the concern. My boss does not agree with the Pico diagnostics ways of doing the job so I don't get much if any experience using the equipment, hence the problems I come up against, such as...

This afternoon after closing time I decided to revisit the Corsa diagnostics. I started by doing a normal compression test using a normal gauge.

Cyl (1) = 210 psi
Cyl (2) = 180 psi
Cyl (3) = 180 psi
Cyl (4) = 210 psi

A drop of 30 psi in two cylinders justifies more diagnostics to confirm/dismiss problem areas to me. I then setup Pico and carried out a relative compression test first. Cyl A 1.00, Cyl B 85%, Cyl C 100% and Cyl D 90%. Each cylinder at the bottom had other data such as 05/2027 but I'm no wiser what that data refers to!

I then carried out a dynamic cylinder balance test, which also indicated two cylinders lower in efficiency than the remaining two. I then decided to setup the WPS500x and do a cranking compression test of each cylinder. Now the problems started...

Using the Pico menu and selecting the WPS transducer and clicking run at the bottom repeatedly gave me problems in that the software would not run. I tried a couple of times but could not get the software to operate until I selected "Automotive" from the menu and then pressure transducers to carryout the test. Each time I did this the software run as normal but if I tried manual setup then the system freezes for some reason.

Each cylinder trace looks the same but two of the compressions are lower asindicated above. A visual inspection into the spark plug holes into the cylinders does not indicate any wetness present at all. Live data on the scanner (Right or wrong) records a manifold depression of approximately 6 psi. Given atmospheric is 14.5 I'd of thought that reading was a tad on the low side!

I've had engines in my life time with compression problems like this but never interferred with the cooling system operation as this one, therefore I'm not convinced the cylinder inefficiency is the root cause of the cooling system behavour at this time, however, I'm leaning towards a defective water pump operation maybe!

It would be really good if anyone knew of a reliable way to test the water pump without labour intensive work to reach a positive result?

Thanks

liviu2004 · Post by **liviu2004** » Sun Aug 28, 2022 5:17 am

Header tank cap tend to fail on these. Thermostat wont open before boiling point at atmospheric pressure, that’s for sure. Cap ensures it remains pressurised system.

Technician · Post by **Technician** » Mon Aug 29, 2022 4:07 pm

Thanks liviu2004 I kept wondering about the cap. It seems to disburse coolant while driving out the header tank cap. I had the same problem a couple years back with a Fiesta. Cap would leak under pressure and a new one also did the very same thing immediately. I then bought one direct from Ford and that fixed it.

Referring back to the Pico cylinder balance test I noticed data under each column. The columns A,B,C and D records what looks like distance measurements in metres (m), however column A seemed stuck at 1.0. Do you know what that means?

The other data I think is possibly referring to cylinder misfire counts at a dynamic engine speed per cylinder. Obviously if a cylinder misfire count is high in comparison to the remaining cylinders then that would be a cause for concern! When I stopped the software running to look back on the misfire data, interestingly the data changed itself to 05/rpm at the time. So I ended with no meaningful data to compare?

Technician · Post by **Technician** » Tue Aug 30, 2022 6:07 pm

Not the cap unfortuently, the cooling system still increases in pressure and records P0087. All hoses and heater operation are okay and blows hot air so not air in system.Either leaking head gasket or water pump efficiency?

liviu2004 · Post by **liviu2004** » Tue Aug 30, 2022 7:20 pm

See south main auto youtube test for blown headgasket using pico and wps500x.

Technician · Post by **Technician** » Fri Sep 02, 2022 6:49 pm

Thanks liviu2004 for the link. I managed to find an old cooling system tester I bought back in the early 1990's from Snap On. Found a coupler and blank and have managed to set it up using the WPS500x. Hopefully now I'll be able to use this setup on most vehicles that become suspect, however the problem becomes comparisons of good data when testing ripple/flow rate for water pumps defects.

liviu2004 · Post by **liviu2004** » Fri Sep 02, 2022 9:16 pm

Here’s the link, apparently you don’t need to go crazy on it, system should build no pressure whatsoever during cranking, if headgasket is in good shape.

https://youtu.be/e93A-O6XV-g

Technician · Post by **Technician** » Sat Sep 03, 2022 5:41 pm

Thanks liviu2004

Technician · Post by **Technician** » Tue Sep 06, 2022 6:07 pm

As I advised earlier I struggled getting the WPS500x to work with the scope. I don't use it that much to be honest so familiarity is lacking, however, today I got the WPS500x and scope to work. It seems my problem is something to do with a connection with the scope, I didn't spot this the other day but today I realised it and think I've isolated the connection problem down to the blue USB port connection connectors on the scope. Now I have got it working I tested the cooling system at idle from cold and the pressure rises continueously. Either the cylinder head gasket or the head/block. More testing would be required to pinpoint but I think the boss will probably just go for the headgasket.

liviu2004 · Post by **liviu2004** » Wed Sep 07, 2022 5:09 am

I don’t think was a good option to do such test with engine running. The video did not show this.

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