1990 G-plate 1.8L Hatchback

[MrSteve]

Well, car runs again!

A few days ago I took off the distributor cap and rotor arm. When I went to put them back on today, the spring and carbon contact were gone. They were there when I took it off!

I eventually found it away from the front of the car (was relieved as decent quality caps aren't cheap). Took a bit of time to coax the spring into the recess in the cap, but got it back in ok.

Thought I'd have a go at starting the car- blow me, it started- and ran! I let it warm up a bit then had to switch off as I had to get my toolbox- I wasn't expecting this!

So I reassembled the air intake, screwed the MSTS back onto its bracket and bolted down the battery.

It took about 3 attempts to restart- and it was different this time because it was catching rather than just cranking over with no sign of life.

I threw caution to the wind and went to get some petrol as it is in the red (treated it to a tank of high octane Super Unleaded), and then got dinner.

Took 2 goes to start at the supermarket, then later I went for a longer drive into the Yorkshire Dales- drove fine throughout and the brake discs got a good work out!

So the Meyle-brand crank sensor works, the original MSTS works, the original ignition amplifier works and the original coil works.

Hopefully I can do the coolant flush and refill this weekend- if it plays ball!

[cavalier1990]

That's a common thing those falling out. Was it in place before when you had the running problem with the ignition fault? Just thinking if you fixed the ignition then lost the cap bush and unknowingly caused another running problem. Had it happen myself plenty of times!

[MrSteve]

That's a common thing those falling out. Was it in place before when you had the running problem with the ignition fault? Just thinking if you fixed the ignition then lost the cap bush and unknowingly caused another running problem. Had it happen myself plenty of times!

Today was the only time it had come out. Never known that to happen to be honest.

Still none the wiser why the car decided to start today. Oh well- it'll go back to not starting any day now...

[MrSteve]

And today the Cav...wouldn't start!

I decided to take the crank sensor out because...why not!

The Meyle sensor, like most aftermarket sensors is made entirely from plastic, unlike the Bosch original. It hasn't aged well in the time it has been on the car- a few months and less than a hundred miles. It is weirdly distorted now.

Meyle after 4 months (O-ring was fitted, but I took it off for the photo:


Bosch original (O-ring binned):


Another difference between the sensors is that the Meyle O-ring is much thicker than the Bosch one.

So the Meyle sensor has warped and distorted due to being less well-made- perhaps enough to be out of alignment with the crank teeth? That could explain the non-starting- a crank signal too weak for the MSTS to decipher?

Doesn't explain why it decided to start and run yesterday though- maybe the MSTS felt like the weak signal was just enough to process for a change...?

The Siemens replacement I got back in August was also plastic, so maybe plastic ones are harder to get sitting level in the crankcase hole?

So I've decided to splash out on a new Bosch sensor- still metal construction, so it should sit in the crankcase hole properly.

So let's see what happens next...

[Robsey]

There is no reason for it to distort like that.
That is just crackers.
I have only ever had 2 crank sensors.
One on each engine, which look(ed) like black factory fit parts.
Both only suffered issues after lifting operations or any other major front end faffing.
Both were fixed by clesning and refitting / re-aligning the sensor, but neither had any odd physical damage like yours exibits.

Looks almost like the sensor has been pulled / stretched. Very weird.
I assume the damage is the same all round? No rub marks or flat spots.

Hopefully the new sensor sorts it for you.

[MrSteve]

New Bosch crank sensor just arrived- part number is 0261210030 if that is of interest.

Here is a side-by-side comparison with the Meyle sensor.



Differences of note:

Thicker O-ring- twice the diameter approx. It also can't slide further up the sensor due to the step in the sensor body.

Thickness of the plastic where the Allen screw goes- plastic version is twice is thick as the metal one.

So with the Meyle sensor even once you overcome the difficulty of getting the short Allen screw to reach the threaded section in the block, it then fails to sit properly due to the fatter O-ring- hence the distortion of the magnetic section caused by the inability of the plastic bracket to resist the bending force applied by the fat O-ring.

I suppose if you removed the O-ring on the plastic-bodied sensor then it would fit better, but then it might leak a bit of oil when running.

Very poor quality part!

Will get the Bosch one fitted this weekend, hopefully.

[iangsi]

You can't beat Bosch components they might be a bit more pricey but worth it, I used a Bosch O2 sensor fitted no problem works perfectly.

[MrSteve]

You can't beat Bosch components they might be a bit more pricey but worth it, I used a Bosch O2 sensor fitted no problem works perfectly.

Looks like the spend on the Bosch sensor has paid off!

Even fitting it felt better- it made a satisfying gentle 'pop' sound as I pushed it home in the crankcase. Allen screw in, then threaded the lead through and clipped it in place. Key in ignition, turned it on and it fired up first time.

Yay- hopefully that sense of dread of will it/won't it start will fade now...!

So looks like the coolant flush, gearbox oil change and selector adjustment can be ticked off the list over the next few weeks.

[cavalier1990]

You can't beat Bosch components they might be a bit more pricey but worth it, I used a Bosch O2 sensor fitted no problem works perfectly.

Looks like the spend on the Bosch sensor has paid off!

Even fitting it felt better- it made a satisfying gentle 'pop' sound as I pushed it home in the crankcase. Allen screw in, then threaded the lead through and clipped it in place. Key in ignition, turned it on and it fired up first time.

Yay- hopefully that sense of dread of will it/won't it start will fade now...!

So looks like the coolant flush, gearbox oil change and selector adjustment can be ticked off the list over the next few weeks.

Great we have lift off - fingers crossed it stays true to form. I'm a stickler for gen parts and this is why!

[Robsey]

Fingers crossed that it is sorted once and for all.
Bosch parts for the win.

Now then, next job on the list - ha ha

I have just ordered one of these myself.
My connector on the camshaft housing is cracked, so a potential weak spot waiting to strike.
I hope that I can wait to fit it until next spring, when I will also fit new timing belt covers.

[cavalier1990]

Is it the same part for all the sohc engines?

[Robsey]

It is same for C16NZ2, C18NZ, C20NE, 20NE and 20SEH.
(So all family II 8 valve SOHC engines).

Not sure about 16 valve, V6 or smaller engines.
(1.4, 1.6 and family I engines).

Although the Bosch part number covers a lot of vehicles including Saab and Chevrolet.

[cavalier1990]

It is same for C16NZ2, C18NZ, C20NE, 20NE and 20SEH.
(So all family II 8 valve SOHC engines).

Not sure about 16 valve, V6 or smaller engines.
(1.4, 1.6 and family I engines).

Although the Bosch part number covers a lot of vehicles including Saab and Chevrolet.

Thanks Robsey, that makes it easier I suppose when if any of us need to order one, it's likely the right one if all the OHC use the same. Regarding the engine sizes, did the very early mk3 cavaliers not have a 1.4 ohc for a wee bit? I'm not sure but it may have been a quick decision to drop it for the 1.6 as the base model.

[Robsey]

Sorry to hog this thread.
I suspect that the 1.4 is indeed an OHC.
My 1.3S in the mk2 was OHC too.
Brilliant piece of machinery.
Small, efficient but fast too.
But I know for certain that my 1.3S did not have a crank angle sensor.
Timing was set by the manual adjustment of the distributor body.
So hence me not being certain what early 1.4 and 1.6 units had. Especially the SV units.

[cavalier1990]

Sorry to hog this thread.
I suspect that the 1.4 is indeed an OHC.
My 1.3S in the mk2 was OHC too.
Brilliant piece of machinery.
Small, efficient but fast too.
But I know for certain that my 1.3S did not have a crank angle sensor.
Timing was set by the manual adjustment of the distributor body.
So hence me not being certain what early 1.4 and 1.6 units had. Especially the SV units.

I do remember getting a shot of a 1.3 cav years ago and surprised how quick it was.

[MrSteve]

Did the coolant flush today, as it has been running plain water (from the dehumidifier) since the fun* I had changing the thermostat in the summer. Also, it runs very hot- it warms up and the needle gradually rises and then stays in the red all the time (thermostat opens and fan kicks in). The needle does move a little within the red zone depending on speed.

I've just fitted a replacement fan switch just in case (Facet part 7.5147), rated 95-100 as per original.

First thing was to get the radiator out and give that a good flush through- pumped water into the inlet and outlet, giving a shake and tipping it from side to side. Water eventually ran clear. Put that to one side.

It took a while for the water in the block to run clear. I had the hose running into the rad outlet hose, into the coolant reservoir and also reverse flow into the thermostat housing.

Connected everything back up and filled with a decent mix of blue antifreeze.

Damn, no change- it still runs very hot in the red once it has warmed up fully.


Things that seem to be correct:

- The thermostat opens around the 100 mark (held the rad inlet hose to check it opens)

- Radiator gradually gets hot from top down to the bottom.

- Rad outlet hose eventually gets hot.

- Heater is roasting- it dried out my soggy socks and trainers just fine over a 40 minute drive.


Things I'm not sure about:

- It takes a good half hour or so of idling for the engine to get hot enough to open the thermostat (dash gauge says around the 100 mark.

- Takes about 45 mins or so for the rad fan to come on (dash gauge in the red).

- On a drive the dash gauge stays in the red and only came out of the red on a long downhill off the throttle. Back in the red on the level.

- Fan kicks in when it gets mid-red bar on the dash gauge- so 110+.


The worry:

The 28-year old water pump has failed and any cooling I am getting is just through thermo-siphoning. The pump isn't noisy and there are no leaks in the system, so it could be that the impeller has come off the shaft?


Looks like I will need to borrow the washing-up bowl to save as much of the coolant as possible and then whip off the pump to see what is happening.

[Robsey]

It does indeed sound like a failed water pump.

The only problem with this is that you have to remove the alternator drive belt, and the timing belt.

Depending on your bank balance, and when they were last changed, it may be worth changing the timing belt and tensioner with the pump.
Maybe also the alternator drive belt for peace of mind.

With the correct tools, it isn't too bad a job to do.
I can probably change the whole lot in under an hour, taking it carefully and if all goes to plan - but cavaliers do like to throw in a few challenges to keep you on your toes.

[MrSteve]

It's an easier job to do, as I've had the cam belt on and off twice so far, and the pump out once to check it and replace the big O-ring seal. Belt is nearly new and the pump is the cam belt tensioner- nice and simple- well done Vauxhall!

Just ran the engine for a bit and stared into the expansion tank. There are no bubbles or oily scum, so I think I can rule out the head gasket.

Just looking on ebay for a decent brand coolant pump. £25-£35 mark gets a Hella (8MP 376 800-721) , an SKF (VKPC 85407) or a boxed GM pump (90272361).

My preference is for the Hella or GM pump as these have a cast metal impeller, whereas the SKF one has a pressed steel one that looks less durable.

Hella/GM


SKF

[Robsey]

If the GM one is available at the right price, it would be daft to use any other brand.

Make sure that the pump comes with a new O ring too.
( I know that I am stating the obvious)

[MrSteve]

Just done a bit of preliminary dismantling- air box out, alternator free, and cam belt covers off.

Then remembered I'd left the spare anti-freeze and water up at my parents...end of play for today!

Tomorrow afternoon I'll get the timing marks lined up, drain the system and then get the pump out .

Though I'll do a touch and sniff test on that staining first- hopefully it's just oil...

[MrSteve]

Pump is out.

And it's not the pump...small trace of weeping at the bottom of the block, but that is it.



Err...

[Robsey]

Hmmm - how odd...
I presume all the pipework has been flushed through.

I cannot see any other causes,
So looking at your checks, in summary -
1 - The cooling fan kicks in around 100 degrees. So the fsn and thermo switch are working.
2 - The water pump is intact and appears to be working.
3 - All air locks said to be purged / removed.

Now the curious bit.
The car takes ages to warm up - which normally hints at a thermostat that failed in the open position.

The car always goes into the red before the fan kicks in.
Only 2 possible reasons.
1 - Faulty sender (single pin / female spade connector).
2 - Inaccurate gauge. I have seen gauges getting up to 103° C on a couple of Vauxhalls before the fan kicks in, but the cars never over heated.
I would expect the'red' area to be 110° C or above.

Does the cooling fin spin freely, or is there some noise or drag.
Normally these fans are very reliable.

[MrSteve]

I've ordered the new water pump anyway- went for the Hella one in the end as the casting matches my original one better than the GM one on ebay. Found one on Amazon or less than £7.

The part number on my pump is 90106599, which doesn't come up on Ecat24. The internet says that is a Holden part number (!).

That arrives on Friday, so I'll get that fitted at the weekend.


I'm also going to get a thermocouple for my multimeter and wrap that round the top hose to see what temp it gets to when running. If it is within a few degrees of the dash gauge then I can rule out that area, I suppose?


With the rad fan, I've only been able to check that with the car stationary. It came on around an indicated 110, I think, so in the red. No idea if it comes on when driving around.


It could be a potential head gasket issue...cylinder to coolant leak- the top hose does bulge a little when super-hot, but maybe I am just worrying!?

[iangsi]

My 1.8 rad fan cuts in when the gauge is barely off the blue mark I've given up worrying about it as I've never had a problem, it's got a newish rad / water pump I flushed the engine block when I changed the pump, flushed the heater matrix still the same, only managed to get the heater to work properly.

[cavalier1990]

Possibility of the thermostat housing section, not the stat front, leaking causing that fluid to run down where the pump is? If I remember rightly it's a seal behind it and runs through the back of the timing belt area to the back where there is a big hose on to it.