C18NZ (Auto) Restoration

[cavalier1990]

Thanks Rob,

I had a look at the throttle body and noticed that the idle filler regulation motor wasn't connected (doh!).

After re-fixing it sounds more like it:

https://drive.google.com/file/d/18nM9PQ ... drive_link

Many thanks (again) for your attention and help.

Cheers

John

That sounds quite good John, always a good milestone when you get it running. Yes, the idle control stepper motor, replaced mine a couple of years ago, seemed to help with the "stuck" high tickover, and occassional bottoming out idle I was getting sometimes.

[jgwilliamson]

That sounds quite good John, always a good milestone when you get it running. Yes, the idle control stepper motor, replaced mine a couple of years ago, seemed to help with the "stuck" high tickover, and occassional bottoming out idle I was getting sometimes.

Hi Andy,
Yes, a promising start. Still got to fit new timing belt, tensioner and water pump along with a new alternator belt then I'll be able to try it with new coolant, oil and filter, and all the air intake stuff plumbed up which will be the proof of the pudding.

Got the rear bumper on today so it's starting to look like a real car again

Just watched your latest video on the Cavalier dash...definitely getting there. Be interesting to see what the actual bulkhead looks like from that side.

Have a great holiday and catch you later

Cheers

John

[jgwilliamson]

Bit of a red letter day.

The Cav made it out of the garage into the daylight for the first time in 18 years, and under its own steam:

Front view: https://drive.google.com/file/d/113qeAF ... drive_link

Offside view: https://drive.google.com/file/d/1Yd8IZ9 ... drive_link

Still the front wheel arch liners to fit and a some fettling of the front brakes which seem to be binding a wee bit.

New water pump, tensioner and timing belt fitted, along with an alternator belt (yes, taking off the engine mounts!!!). New alternator fitted as well and after that all the ignition lights came on and then (more importantly) went off again after it started.

Everything seems to be working, however have yet to see the radiator fan kick in. Does anybody know when that is supposed to happen? The temperature gauge got above 90 and probably nearer 100 but nothing from the electric fan.

The engine idles exactly at 1000rpm. I think I remember reading somewhere here that is expected for an auto compared to a manual.

All in all well chuffed Now for the "detailing" !

Cheers

John

[Robsey]

The temperature that the fan kicks in at is around about the late 90s °C.... 96°C or above,

BUT
Temperature gauges are only a rough guide - not very accurate.
I have seen the needle reach an indicated 103°C before the fan kicks in on some Vauxhalls.
But I wouldn't want it to go any higher than that.

[jgwilliamson]

Hi Rob,

I removed the fan about 15 years ago and cleaned it up and tested that the motor run again a battery (which it did). I'll need to do that again.
If that's OK and it's still not working have you any advice about testing the thermostat that enables the fan motor?

Cheers
John

[Robsey]

All you can do to test the thermo-switch, is to take it out of the radiator.

Put a test meter across the pins, and pour boiling hot water over the sensor side.
You should have infinite resistance - open circuit.

Just as it approaches the boiling point, the switch should close internally, giving only minimal resistance across the pins.

[jgwilliamson]

All you can do to test the thermo-switch, is to take it out of the radiator.

Put a test meter across the pins, and pour boiling hot water over the sensor side.
You should have infinite resistance - open circuit.

Just as it approaches the boiling point, the switch should close internally, giving only minimal resistance across the pins.

Thanks Rob

[jgwilliamson]

Evening all,

I tested the fan motor by wiring it up direct and it's going OK.

Before I drain the coolant and remove the thermostat switch I wonder if anyone can explain the following:

1. The thermostat switch connector has 3 wires into it: brown, brown and white and brown and yellow (see photo)

https://drive.google.com/file/d/1YPrnwQ ... drive_link

2. The thermostat switch fitted to the radiator however only has two pins/blades (see here):

https://drive.google.com/file/d/1LE6O_R ... drive_link

From what I can see only the brown/white and brown wires will be connected to the switch?

The online EPC gives 7 different types of switches - idents WJ, WU WP, WM WH, XC, XD.

https://opel.7zap.com/en/car/j89/f/0/3-1/

Anybody know what all that is about?
Have I got the correct thermostat switch?

TIA

John

[Robsey]

Hi John,

I will have a look when I get in from the unit.
(Early hours of the morning).
I know my manual 1994 C18NZ had a simple two-pin thermo-switch.

Because of the heat generated by the torque converter, it would not surprise me if you have two-stage thermoswitch.

I will put your reg through my EPC software.
Or if you want it more accurate, you could private message me your VIN.

Cavaliers are not all recorded, but worth a look.

[jgwilliamson]

Hi John,

I will have a look when I get in from the unit.
(Early hours of the morning).
I know my manual 1994 C18NZ had a simple two-pin thermo-switch.

Because of the heat generated by the torque converter, it would not surprise me if you have two-stage thermoswitch.

I will put your reg through my EPC software.
Or if you want it more accurate, you could private message me your VIN.

Cavaliers are not all recorded, but worth a look.

Hi Rob,

Many thanks again. I have sent my VIN in a PM.

Cheers

John

[Robsey]

Hi John,
I have found your car in EPC.

Manufactured at Luton in 1993.

I have checked all 34 pages of the cooling system.Strangely it pulls up a switch assembly for C25XE as the only compatible part.

Part number is 90 339 414
Switch Assembly, Water Temperature (Ident WH).



For info, it looks like you have a two-speed fan
Wires are as follows.

Brown - Ground.

Brown White - Cooling Fan speed 2 direct from blower motor.

Brown Yellow - Cooling Fan speed 1 from blower motor via a ballast resistor.

Your thermo switch is a dual temperature switch.

Fed by fuse 24 in the fusebox under the bonnet.

[jgwilliamson]

Hi John,
I have found your car in EPC.

Manufactured at Luton in 1993.

I have checked all 34 pages of the cooling system.Strangely it pulls up a switch assembly for C25XE as the only compatible part.

Part number is 90 339 414
Switch Assembly, Water Temperature (Ident WH).

For info, it looks like you have a two-speed fan
Wires are as follows.

Brown - Ground.

Brown White - Cooling Fan speed 2 direct from blower motor.

Brown Yellow - Cooling Fan speed 1 from blower motor via a ballast resistor.

Your thermo switch is a dual temperature switch.

Fed by fuse 24 in the fusebox under the bonnet.

Hi Rob,

Thanks very much for taking the time to check this out for me.

I now realise that there are a few "gotchas" to look out for sourcing parts for an auto C18NZ as opposed to a manual (front discs, brakes etc).

(Nothing is ever straight forward with car restoration is it?)

All the best

John

[Robsey]

95% of your factory schedule is identical to mine.
August 1994 C18NZ - 1.8LSi hatch.

The brake pads confused me too, when I had mine restored 6 years ago.

The real difference is due to the auto-box as I suspected earlier.

'Straight forward' is boring.
A bit of variation makes it more interesting.

[jgwilliamson]

Quick update on thermostat switch:

Replaced 2 pin WJ switch with 3 pin WH switch and fan now switching on and off at the appropriate temperatures

[Robsey]

Excellent news.
Another box ticked.

[jgwilliamson]

Another milestone day:

1. Fixed radiator thermostat problem (see above)
2. Fitted new front suspension arms and anti roll bar bushes
3. Sorted "sticky" throttle cable (* this was a good one)
4. Fixed "drag" on front brakes and disc (due to tight hub carriers)
5. Changed oil and filter

So, the only thing between the Cav and MOT pass (hopefully) is the OS side repeater bulb which is blown. To say I'm chuffed would be an understatement

Cheers,

John

* - The cable had ended up in an "S" bend at the front of the brake fluid reservoir. By simply feeding it behind the reservoir the problem resolved itself. Simples

[jgwilliamson]

Excellent news.
Another box ticked.

[jgwilliamson]

Well the Cav went in today for it's first MOT since 2004 and it failed (see below):

>>>>>>>>
Do not drive until repaired (dangerous defects):

Nearside Rear Tyre has a bulge, caused by separation or partial failure of its structure (5.2.3 (d) (ii))

Repair immediately (major defects):

Exhaust carbon monoxide content after 2nd fast idle exceeds manufacturer's specified limits (8.2.1.2 (a))
Exhaust Lambda reading after 2nd fast idle outside specified limits (8.2.1.2 (c))
>>>>>>>>
None of the above was entirely unexpected and I've got a new catalyst on order which should sort the CO defect and hopefully the Lambda reading unless there's a leak elsewhere.

Not too disappointed as I took it for a 8 mile run just before the test and it was driving great.

Getting there

[jgwilliamson]

Well, after a fairly long drawn out MOT (the cav went in last Tuesday), it has finally passed the MOT for the first time since 2004

A new set of tyres and a new B&M type approved cat is what it took to get it over the line. Happy days.

After taxing it (ouch!), I've been "out and about" with it, driving with an attentive ear (as we all probably do with these older cars), and it performed admirably. I have forgotten the RPM speed/auto gear selection as it's been a while since I last drove it on the "Kings Highway", so I'll have to get used to that again, but it didn't seem a cause for concern (any help/info in this would be appreciated).

A couple of things that did come up:

1. Robsey's dreaded "hot idle oil pressure light" problem seems to be present. Admittedly it is a barely imperceptible flicker after a run, and the oil dipstick looks fine. A connection problem perhaps?

2. Cold and hot Idle speed seems a wee bit higher with the new cat (just under 1200rpm) than with the old one (1000rpm). Anything to worry about?

It's great to be back in the seat of one of my favourite cars, and to help contribute against the decline of these fine motors on our roads.

Paintwork and trim next

A couple of pics from earlier today:

https://drive.google.com/file/d/1CxRKSk ... drive_link

https://drive.google.com/file/d/1JnwSgU ... drive_link

Cheers John

PS Many thanks to everyone here who helped me get this far with the old buggy

[Robsey]

Congratulations on the pass.
Brilliant news.
That is a lovely colour.

Fast idle - sticky throttle cable perhaps.
Idle speed should be about 880 rpm +/- 80 rpm.
Is the idle speed higher when in drive?
Otherwise, just check the condition of the vacuum pipes and rubber elbows between the air-filter housing, injector top-hat and the injector body. (Throttle body).
The elbows are very brittle.

As for the flickering oil light.
As long as the light goes off when you come off idle...it will be fine. Say above 1750 rpm.

[jgwilliamson]

Congratulations on the pass.
Brilliant news.
That is a lovely colour.

Fast idle - sticky throttle cable perhaps.
Idle speed should be about 880 rpm +/- 80 rpm.
Is the idle speed higher when in drive?
Otherwise, just check the condition of the vacuum pipes and rubber elbows between the air-filter housing, injector top-hat and the injector body. (Throttle body).
The elbows are very brittle.

As for the flickering oil light.
As long as the light goes off when you come off idle...it will be fine. Say above 1750 rpm.

Thanks Robsey,

I'm well chuffed

I'll check out your suggestions and let you know. I'll probably be driving it as my "daily driver" until the winter, so hopefully "tease out" a few more niggles, but I'm confident it will be fine. (They really are good cars).

BTW Many thanks for all your help.

Regards

John

PS Colour is "Lagoon Blue". My wife originally preferred a Burgandy metallic colour but that car went so we had to settle on this one. My missus still doesn't like it (after all these years !). However like you, I like this colour