OT cambelt replacement

[js.b1]

If the engine is "interference" the end result is costly. Typically =A31000-1400 for the top-end work, but in most cases bottom- end work *should* be done.

In an interference engine the piston hits the valves, bending the valves and in many cases causing damage to the main bearings. Alfa Romeo and Honda state that not replacing the main bearings will result in main bearing failure within 1 year.

From an imbecile Arts relative I can confirm a) backstreet garages will do the job for =A3900 b) will trash the power steering pump by getting rubbish in a hose c) will not replace the main bearings with the engine making "an odd noise on the M4" d) shortly followed by catastrophic failure of the engine and e) said imbecile believed the police would recover the Alfa junk and not bill him for doing so. So much for Arts Degrees.

Now, it is not just "a cam belt job".

- Generally the water pump is done at the same time, because the steps are the same and a pump is =A328-67 (usually the latter if a new pulley/ bearing kit is required)

- Generally the hydraulic tensioner is replaced if it fails to comply with a load/movement test in the workshop manual, because the steps are the same and they are =A372-160. A pin (nail) is required to hold the thing compressed, removed once in place.

Why is the hydraulic tensioner important? The tensioner provides tension based on oil pressure and thus engine RPM. A failing tensioner can result in timing belt or chain failure EVEN if it has been replaced. Tensioner failure can destroy the cam cover which is typically a silly price.

It is generally 3.5-4hrs labour to do a timing belt. FWD access via the wheel arch, make sure you put the tray back correctly or you will get salt/mud buildup in the upper apron which will rot out very quickly on the near side and pretty quick on the offside. Generic parts should be ok, but always check the appropriate vehicle forum. You need few tools, good extract of the workshop manual (which you can buy), and a torque wrench. Best to do over a couple of days.

[airsmoothed]

My two Vectras and the two Omegas before (all mid to late 90s vintage) all behaved as I would expect, guage rises to about 80 fairly quickly and stays there unless you're sat in traffic. OTOH I used SWMBO's Zafira today and the only time the gauge moved noticeably off the end stop was sat in heavy traffic on the M3. yet I'm 100% sure the thermostat works. Guy I knew with a 2003 ASTRA swapped the thermostat and it still acted that way, seems Vauxhall meant it to act that way, even though it makes the car seem overcooled. Lucky to get an actual temperature gauge on a modern car mind you!

[The Natural Philosopher]

my Vauxalls both simply smashed the rockers. the belt let go at very low RPM in both cases. The valves were simply driven up hard and bent slightly. Both did considerable mileage with no further issues.

Why? there is no real need.

That depends on whether it has such. Its by no means a standard feature

That may be true for alfas, but its not generally true. I think we had one done on the Punto for very little money by a main dealer.

In some cars is simple end cover off, remove belt holding camshaft in position. slide new belt on job, holding tensioner (if there is one) away from belt, replace cover job done.

It all depends on the engine and installation really. Main dealers will do a 'guaranteed' job and replace everything in sight and use it as an excuse to stiff you blind sometimes.

But a good backstreet man will replace only waht is necessary and tell you that that is all he has done.

[T i m]

Ok.

Hmmm. ;-(

Ok, I've changed the temperature sender and measured both the old and new and found they were on spec:

've put the old sender in hot water when hooked up to the temperature gauge and it appears to read fairly well (considering how basic they are etc).

Do you think it's likely that Vauxhall put a gauge in where the needle doesn't even enter the gauge under 'normal conditions'?

(FWIW I thought it was common practice to have such indicators reading 'straight up' when in the 'normal / good' condition)?

I don't think it's unheard of to have more than one faulty stat (my mate tests them before he fits them these days).

Hmmm.

Well that's true (we had a Ka for a year or so).

Googling about some more I've found several references like this:

".. turned out to be the thermostat. It now heats up quickly to the mid way 90 mark and stays there regardless of speed or outside temp .."

Which is what I would expect any engine to do when working properly and has in all the cars I've ever owned (over 30+ years). As you said previously though, things are a changing ... ;-

Not saying there is a problem but my gut feeling is something isn't right though.

Cheers, T i m

[js.b1]

Depends on the car. Some water pumps last 40k (some porsche, volvo), some last 100k. Will be interesting to see how long electric water pumps last.

Where timing belt life is close to water pump life, generally both are done rather than "wait for the wee out of the weep hole" and smell of hot coolant on a (usually) freezing cold winter's morning.

Many do, and it is a finite life item.

Jack under oil pan with plank of wood, jack engine a little, remove engine mount, then remove cam belt cover, then compress tensioner, then remove old belt. Depends on how much junk is in the way.

Some actually do clutch and timing belt ok... ... but then screw you exhausts, anti roll bar linkages, hoses, hoses, wheel bearings, cv boots, cv joints, shocks etc :-)

Seems to be a "get some trust, then screw them once they are doe eyed" :-)

Sometimes belt life is critical. Some Volvo mandated replacement at 42,000 miles and even 12-28 miles past would grenade.

Sometimes belt life is far longer. California spec cars often quote a 100,000 mile life because that is mandated on emissions components (and a timing belt is considered an emissions component). There is no different part number for the belt, so with non-interference engines in particular people just ignore the "60,000 mile suggested interval).

Many cars use a bypass thermostat, so the needle behaviour can be a little odd.

[T i m]

I'm guessing no 'so odd' as to make the needle sit off the bottom of the gauge once the car is moving (even / especially at motorway speeds)?

45k 04 Meriva 1.6 8V.

Cheers, T i m

[Jules Richardson]

There was also some trick involving cutting the old belt down the middle, then you could slide the new belt on without the possibility of misalignment (then old belt was cut entirely off and new one slid entirely into place). I'm not sure it's really worth the hassle though...

Yes, that's where we're at with the Toyota - non-interference engine with about 250k on it, belt was due at either 150k or 180k, so it's running quite a bit beyond design life...

cheers

Jules

[grimly4]

I know from direct experience, the Escort 1.8D engine would lunch its tensioner, belt and top end at a shade over 60K miles. Almost without fail, until Ford dropped the recommended mileage for change. In contrast, the previous 1.6D engine's cambelt lasted forever and damn few were changed.