Corsa D oil pressure

[Red'n'Black]

Just bought one of these, on a 09 plate for my youngest as a first car. At this price point if it lasts a year I'll be happy, better to get the inevitable scrapes and dings out of the way on something cheap.

I got a horrible sinking feeling on the trip home when the oil pressure light started coming on randomly. But a bit of Googling suggests the pressure switch is a weak spot on these and it runs smooth and quiet, no other symptoms.
Once I got it home I bodged up a pressure gauge, it showed 5 bar at idle, not quite stone cold, rising to about 5.5 when revved.

Strikes me as quite high if anything? I didn't leave it to see if it dropped as it warmed up as my bodged gauge connection was weeping a bit much for my liking.

A tenner or so for a new switch isn't going to break the bank, but is there anything else I should be checking?

 

[Haz87]

Pointing out the obvious really, but you need to work out what the actual hot pressure is. No point tearing into anything until you've determined that

 

[Red'n'Black]

Pointing out the obvious really, but you need to work out what the actual hot pressure is. No point tearing into anything until you've determined that

Ok, attempt #2. Adaptor re-made with a proper sealing face.

There's no temperature gauge in these, so I kept an eye on it with an OBD reader. Peaked at 115C before the radiator fan kicked in, I read this engine is designed to run quite hot?

Hot pressure at idle was 2.2 bar, rising to 5 at 3000 rpm. Seems a lot more reasonable.

Another clue that the switch was toast was the dribble of oil that came out the back of the connector.

New switch fitted and light stays out, I think I can stop fussing about this one now.

Which brings us to the next thing, it's losing coolant at a rate of a header tankful in 50 miles. No obvious leaks that I can see. None of this showed up on the test drive, obvs.

Test kit ordered for combustion gas in coolant. Watch this space...

 

[Barking Mat]

Ok, attempt #2. Adaptor re-made with a proper sealing face.

There's no temperature gauge in these, so I kept an eye on it with an OBD reader. Peaked at 115C before the radiator fan kicked in, I read this engine is designed to run quite hot?

Hot pressure at idle was 2.2 bar, rising to 5 at 3000 rpm. Seems a lot more reasonable.

Another clue that the switch was toast was the dribble of oil that came out the back of the connector.

New switch fitted and light stays out, I think I can stop fussing about this one now.

Which brings us to the next thing, it's losing coolant at a rate of a header tankful in 50 miles. No obvious leaks that I can see. None of this showed up on the test drive, obvs.

Test kit ordered for combustion gas in coolant. Watch this space...

What mileage ?

 

[jmp49]

I dont know the diesels to work on, but the 1.6 XEP petrol runs at 115c before the fan kicks in, and it also controls the radiator thermostat from the ecu by heating up a wax capsule to open the stat electronically. If you have the slightest loss of pressure it will quietly steam away the contents of the header tank...
The XEP that I did had the same symptoms, but it had a bad head gasket and warped head with worn out guides and a load of other issues, and I ended up putting a scrapyard engine in.
On the astra there's a secret menu accessed by a button combo on the radio, that displays the temperature right on the little info screen. You have to do it every time you turn it on, but its handy.
Corsa's the same it seems :

Hidden Menu Info - all in one place

Just thought I would put this all together as i find myself keep using the search function to find the correct threads. Key Fob Hold down the open button and the windows will go down for as long as its held pressed Hold down the lock button and the windows will go up for as long as its pressed...

www.ukcorsa-d.com

 

[Red'n'Black]

What mileage ?

110K

 

[Red'n'Black]

I dont know the diesels to work on, but the 1.6 XEP petrol runs at 115c before the fan kicks in, and it also controls the radiator thermostat from the ecu by heating up a wax capsule to open the stat electronically. If you have the slightest loss of pressure it will quietly steam away the contents of the header tank...
The XEP that I did had the same symptoms, but it had a bad head gasket and warped head with worn out guides and a load of other issues, and I ended up putting a scrapyard engine in.
On the astra there's a secret menu accessed by a button combo on the radio, that displays the temperature right on the little info screen. You have to do it every time you turn it on, but its handy.
Corsa's the same it seems :

Hidden Menu Info - all in one place

Just thought I would put this all together as i find myself keep using the search function to find the correct threads. Key Fob Hold down the open button and the windows will go down for as long as its held pressed Hold down the lock button and the windows will go up for as long as its pressed...

www.ukcorsa-d.com

Yes I saw that in the manual.

This one is the 1.2 petrol. Apparently a common fault is a gasket at the back of the water pump failing and leaking the coolant into the timing case. But the water pump looks brand new.

I have a nasty feeling the seller has missed the leak until it was too late, then tried all the easy fixes, given up and sold it on. I hope I'm wrong. We'll see...

 

[jmp49]

Ah the D threw me, I was thinking of the Corsa diesel. I think that will be a A12XER engine, little bit different to the 1.4 and 1.6 as the bigger bretheren have the water pump externally mounted driven by the auxillary belt but its still a ecotec twinport motor and same sort of electronics and active cooling system. They run stinking hot by design for emissions reasons, that was part of the big revision between Astra Ecotec G and Ecotec H motors.

If its still leaking at that gasket then that could be the source of the pressure loss, and also why its consuming coolant.
Check the oil for traces of contamination of course & could be worth putting a pressure tester on the system too, however the bad Astra motor only leaked when it was stinking hot after we fixed the worst of the leaks and fitted a new pump so we kept missing it at first till the sniff test smelt exhaust gasses in the coolant which you mentioned you were going to do. The bad motor had 160k on it, and would have been saveable if the previous owner hadn't been numpties and driven it round baking itself for months. As with most cars, its not the mileage, its how its been treated for those miles...

Vauxcom is really really good if you want to get a full diagnostic setup, you can basically monitor and alter anything in it, reprogram keys/immobilizer etc but (if I remember correctly. its been a while and a few different diagnostic software blurs ago...) you need the security code that ships on the radio card when the car is new to unlock some reprogramming features and odds are its missing (they always used to be missing when we took company fleet cars back at a year old, never mind now). You can order this card separate from a vauxhall dealership after providing proof of ownership of course. There's a virtual machine setup with vauxcom inside it all set up and working on the net you can find for download easy, you need a opcom interface then, which are fairly cheap, but not all of them work properly... And a old laptop to run the virtual machine on too.

 

[Red'n'Black]

Not sure what to make of this one.

The CO2 test kit turned up, but came up negative. Started with it partly warm as suggested, a few bubbles came through but that was just the air in the header getting displaced. I had to stop after 5 minutes when it came up to temperature and coolant reached the top of the filler, I think this is normal as the system wasn't sealed.
Solution stayed blue. I blew through the other end of the tube afterwards and it turned yellow straight away, so definitely working.


I still wasn't sure where the coolant was going.
Apparently they can leak into the timing case through the back of the water pump, but the oil level hasn't moved and is nice and clean, no sludge or mayo.

Went and bought a leakdown tester.
Pressurised each cylinder in turn per the instructions, with a piece of cling film secured over the filler. Left each one for a few minutes, but readings were all normal, no bubbles in the coolant and the cling film didn't even move.


Plugs look OK and all about the same.



Something has happened to #4 at some point though, by the looks of it.



Pulled all the hoses off and gave the whole system a flush through. All seems to run freely, no obvious blockages.

The one place I can see signs of a leak is under the thermostat housing. Not clear which of the two hoses is leaking, but one of them looks like a pair of old flares.



Took the thermostat out and put it in a pan on the stove, opens normally just before the water starts boiling.



That brown stuff isn't rust but some sort of oily residue, it just wipes off.

So I think the evidence is pointing to it having a blown gasket at some point, and the previous owner put some Radweld type stuff in it. Which seems to have sealed up the HG, but they haven't finished the job and dealt with the perished hoses. Which is a bit weird.

My inclination is to put it back together with new hoses, clamps, cap and thermostat (O ring looks a bit iffy as well) and take it from there.
The water pump I wasn't going to touch, that looks brand new.

Anything I've missed?

 

[dobbslc]

Heater matrix?

 

[Red'n'Black]

Heater matrix?

Wouldn't the carpet be wet? And windscreen all misted up?

I did flush that through as well, no blockage that I could see. I could pressure test it and make sure I suppose.

 

[rtcosic]

I have often wondered about adding fluoroscent dye to the coolant to trace such obscure leaks:

https://www.screwfix.com/p/monument-tools-fluorescein-drain-dye-133g/31595?tc=VA6&gStoreCode=VA6&gQT=1#product_additional_details_container

 

[Melvyn Best]

I have often wondered about adding fluoroscent dye to the coolant to trace such obscure leaks:

https://www.screwfix.com/p/monument-tools-fluorescein-drain-dye-133g/31595?tc=VA6&gStoreCode=VA6&gQT=1#product_additional_details_container

It works well if you have a UVA torch

 

[jmp49]

I use uv dye in the coolant (and oil, aircon system etc, different dyes for each type) and a torch like this as posted elsewhere, and lad's z16xel equipped astra had a tiny leak out of one of the unions where it was flared like yours when we first started hunting the overheating. It doesnt take much pressure loss to let the coolant boil and steam off as they run so hot & all the hoses seem to go hard afterwards from it.
On that I cleaned up the corrosion on the barb and the end of the hose, and put a new clip on it and it sealed after but ended up replacing the hose anyway when the motor was taken out for a replacement when it failed the sniff test afterwards anyway...

You mentioned the obd2 reader for temp control, have you rechecked for any fault codes? the active cooling not working can also cause this, but it throws a bunch of codes depending on how its not working.
The astra had blown a fuse in the engine fuse box that took out the o2 sensors, the thermostat etc, but it didnt have a CEL lit, just a warning light that extinguished that the manual said was o2 sensor heating but when we put vauxcom on, 8 sensors had codes related to them & it was the thermostat heater shorting out when hot causing the fuse to blow (and probably what killed the motor for the original owners who just drove it like this for months).

 

[dave h 2]

Wouldn't the carpet be wet? And windscreen all misted up?

I did flush that through as well, no blockage that I could see. I could pressure test it and make sure I suppose.

A clue for that would be hot antifreeze smells sweet.
The best hose leak that I ever had was the top hose pin holed spraying the distributor with a very fine jet you could barely see.

 

[Red'n'Black]

I use uv dye in the coolant (and oil, aircon system etc, different dyes for each type) and a torch like this as posted elsewhere, and lad's z16xel equipped astra had a tiny leak out of one of the unions where it was flared like yours when we first started hunting the overheating. It doesnt take much pressure loss to let the coolant boil and steam off as they run so hot & all the hoses seem to go hard afterwards from it.
On that I cleaned up the corrosion on the barb and the end of the hose, and put a new clip on it and it sealed after but ended up replacing the hose anyway when the motor was taken out for a replacement when it failed the sniff test afterwards anyway...
View attachment 495634
You mentioned the obd2 reader for temp control, have you rechecked for any fault codes? the active cooling not working can also cause this, but it throws a bunch of codes depending on how its not working.
The astra had blown a fuse in the engine fuse box that took out the o2 sensors, the thermostat etc, but it didnt have a CEL lit, just a warning light that extinguished that the manual said was o2 sensor heating but when we put vauxcom on, 8 sensors had codes related to them & it was the thermostat heater shorting out when hot causing the fuse to blow (and probably what killed the motor for the original owners who just drove it like this for months).

No fault codes that I can see, but my kit consists of a cheapy Bluetooth adapter and a copy of Torque on my phone.

Yesterday I fitted new top and bottom radiator hoses, new thermostat and header cap. The stat is just a wax type, no electronic controls that I can see, unless there's another one somewhere?

First proper run this morning and it's still losing coolant - but this time the leak is obvious, but hard to pinpoint as the wind has blown it all round the engine bay.

Took it for an extended test drive tonight and finally found the leak, it's dripping from where the top hose meets the rad. So either I've not done the clip up properly or there's a hairline crack in the plastic. We'll soon see.

 

[badabec]

Where is your youngest whilst all this is going on?

 

[Red'n'Black]

Where is your youngest whilst all this is going on?

Taking a keen interest so far. Doing the driving on tonight's expedition, so I could watch the live data on my phone. Always asking questions, what's that do, what does that mean, etc. She'd happily do a lot more, but revising for A levels needs to take priority for the next few weeks really.

 

[Red'n'Black]

This is doing my head in.

I thought I was onto something - found a hairline crack in the rad, next to the top hose spigot where it had been leaking.
New rad bought and fitted. All looks OK warming up, no leaks, so take it for a run while logging live data on my phone, 17 miles to the nearest town and back. Stopped for a few minutes to have a look at the fluid level, then head home. No leaks that I can see, all looks good.
It was when I pulled back onto the road it all went bananas. Temperature spikes to 120+, warning light comes on, then after less than a minute it all goes down again and behaves sort of normally for the rest of the trip.
Pull into the driveway and leave it idling, temperature was > 110 and still creeping up and the occasional bubble coming up through the tank, even with the fan on full chat. I shut it off at that point.

I had a look at the log. Seems OK on the open road, it starts to struggle at low speeds and when stopped. All seemed to point to a lack of airflow through the rad.

Pulled the bumper off again and had a closer look at the aircon condenser, which didn't work when we bought it. Sure enough, all coroded and clogged with dead bugs etc.
A quick test of the pressure ports showed the system was empty, so I just removed it. Reassembled everything and went out again, on the exact same route.

It looked better at first, but then started shooting up to 120+ again, seemingly at random.
Back home, temperature still creeping up, tried turning the heater on full. Temperature still creeping up.
I wasn't sure if the temp sensor was telling me porkies at this point, it doesn't seem physically possible for the block temperature to change that fast, so unplugged it. Went off the bottom of the scale as expected.
Plugged it back in, by now the temperature was heading way down below normal, fan still on full chat as disconnecting the sensor probably put it in fault mode.
Stopped and restarted, left it idling while the fan cycled on and off a couple of times, all now seems absolutely normal.



The only thing I can think of now is something stopping the coolant flow -
Pump impeller loose on the shaft? Pump looks brand new but who knows where it came from? Fitting another new one looks like it involves a fair amount of dismantling.
Lump of Radweld that randomly gets lodged against the pump outlet?

Mrs and the little'un are now on the point of chucking in the towel and buying something else. Unless anyone can think of something easy I've missed?

 

[Ace Paul]

You seem intelligent reading this.

A) replace the cooling cap if you haven’t
B) if possible drill hole in old cap fit schrader valve, when engine warm pressure the system. 15psi. See if can see a leak.

As it’s leaking anyway, Can you drain coolant and refill with food dye and water?

(Check it don’t turn to gel)

Not sure what car. Jack up. Look at bottom of top hose/thermostat