2002 Opel Combo 1.7Di Problems

52paddy

Hi all,

I bought an Opel Combo a few weeks ago and have since found two problems which I'm hoping to figure out.

1. The heater doesn't work to its full extent. The temperature does change with the setting dial but on full heat, it's only luke-warm. None of the heaters for your body work satisfactorily (blow very little air), the windscreen demister vent seems to work OK but haven't had properly bad weather to test it yet and the foot vent works only about the same as the body ones. Seems like something is obstructing the flow of air...?

2. There is a good deal of black smoke when I rev it in neutral. This is also noticeable on occasion when I'm driving on motorways at 50-75 mph for a few minutes. I've been told it could be dirty injectors and have been advised to throw some diesel injector cleaner into the tank and will do this soon. I'm also suffering a loss of power so am thinking the problem is linked. It's not too bad when driving on flat roads but, at its worst, I have to be in 1st gear when starting to go up Knockmaroon Hill.

Thanks.

shamwari

1. Assuming the fan is working correctly on all speeds then I would look at replacing the pollen filter first. This usually sorts out any air flow problems through the heater. If there is a general lack of heat thereafter with the engine not reaching operating temperature then you might be looking at changing the thermostat. It's unlikely that it will need bleeding as the top two pipes onto the coolant header tank let that system purge easily. But on some of the older Isuzu based engines (yours is one BTW) there might be a bleed point on the thermostat housing to purge air in or around it.

2. Those engines can be a tad smokey, especially if they have been neglected. A good dose of injector cleaner and a general service with new oil and filters all around would also be a good start, followed by a "lively" run on the motorway (keep with the speed limits but use a lower gear and let the "blast" clean it out ) If it still smokes and is down on power then an intake leak or sticky EGR would be likely. IIRC most of the intake on those is metal rather than flexi-plastic and very rarely leaks. Does it sound boomy under full throttle? Has the engine management light come on?

One other troublemaker on those is airflow meter and they tend to cause the engine to be dead below 2000rpm. It's hard to say if this is a factor here though with the cars power issue.

52paddy

shamwari wrote: »

1. Assuming the fan is working correctly on all speeds then I would look at replacing the pollen filter first. This usually sorts out any air flow problems through the heater. If there is a general lack of heat thereafter with the engine not reaching operating temperature then you might be looking at changing the thermostat. It's unlikely that it will need bleeding as the top two pipes onto the coolant header tank let that system purge easily. But on some of the older Isuzu based engines (yours is one BTW) there might be a bleed point on the thermostat housing to purge air in or around it.

2. Those engines can be a tad smokey, especially if they have been neglected. A good dose of injector cleaner and a general service with new oil and filters all around would also be a good start, followed by a "lively" run on the motorway (keep with the speed limits but use a lower gear and let the "blast" clean it out ) If it still smokes and is down on power then an intake leak or sticky EGR would be likely. IIRC most of the intake on those is metal rather than flexi-plastic and very rarely leaks. Does it sound boomy under full throttle? Has the engine management light come on?

A very well laid out and informed answer. Thanks for you advice.

In relation to the heater, I'll replace the pollen filter and see what happens.

Engine-wise, I've been recommended throwing in diesel cleaner and it definitely does need a oil + filter change. Air filter is fine. So I'll do that before jumping further into the internals. No "boominess" under full throttle - it sounds fine. The engine management light doesn't come on usually though the "service" light (a spanner icon, not sure if it's the same light on these cars as EM) did come on a few weeks ago when I had it flat out on the motor way (90+ mph). When I reached my destination and left the car parked for a few hours, the light didn't come back on thereafter and I've only been driving in speed-limit conditions since.

Another problem arose today which I would like to point out:

The brakes failed to work. The pedal became really hard to press and I couldn't achieve any braking action. Today, it was raining quite persistently. This exact same problem happened some weeks ago when it was raining at a similar rate but has not happened again until today (don't think I drove it in very heavy rain since the last time, as it turns out). I wonder is there a link here with significantly wet conditions.

There is a proper amount of brake fluid in the reservoir. I've not checked the conditions of the pads, discs or lines yet. I've read that oil leakages from a seal on the braking system can seep onto the pads and affect braking but surely this would have created a less intermittent problem and have been consistent in dry weather also? I'm not a mechanic, just guessing. Any help appreciated.

shamwari

Your brakes problem sounds like an issue with the brake vacuum pump which (again if I'm correct) is on the back of the alternator. There's a heavy black pipe coming from it to the brake servo. It's simple to test: remove it from the servo, start the engine, and cover the pipe with your thumb. If its working you'll feel the suction in the pipe under your thumb. If there's no or weak suction then

the alternator belt might be slack (or getting wet and slipping! ) orr
the car is low on oil or
the vac pump is duff or
the vac hose is leaky somewhere.

What worries me about those vac pumps is that if they fail, the failure is a silent one till you go to use the brakes. And that aint no fun at all...:cool:

52paddy

Cool man, thanks again. I'll report back in due course!

52paddy

Update:

- I removed the pollen filter and ran the fan. It's working fine now so will replace the filter soon.

- My dad thought the brake issue could possibly be a seized master cylinder so we took it out and oiled the piston. Then, we bled the brakes (except for one wheel as the alloy nut on the bleed system is seized) and topped up the fluid. The brakes work in dry weather, as per usual, but I drove it in rainy weather since and had a similar problem. I didn't get a complete brake failure but the pedal still became hard and, when pressed as much as possible, I'm getting about 17-20% braking efficiency. I'll check the vacuum pump next time I'm working on it. Failing that, could it be a wheel cylinder? The wheels are in awful shape. There's lots of rust on them and taking of the wheel bolts was a job in itself. In fact, I've yet to get the offside wheel removed as I broke my wheelbrace attempting it!

shamwari

52paddy wrote: »

Update:

- I removed the pollen filter and ran the fan. It's working fine now so will replace the filter soon.

- My dad thought the brake issue could possibly be a seized master cylinder so we took it out and oiled the piston. Then, we bled the brakes (except for one wheel as the alloy nut on the bleed system is seized) and topped up the fluid. The brakes work in dry weather, as per usual, but I drove it in rainy weather since and had a similar problem. I didn't get a complete brake failure but the pedal still became hard and, when pressed as much as possible, I'm getting about 17-20% braking efficiency. I'll check the vacuum pump next time I'm working on it. Failing that, could it be a wheel cylinder? The wheels are in awful shape. There's lots of rust on them and taking of the wheel bolts was a job in itself. In fact, I've yet to get the offside wheel removed as I broke my wheelbrace attempting it!

I cant remember where the pollen filter is on those (whether its inside or outside) but if its outside I suggest replacing it as soon as you can because you could end up with water in the car in heavy rain.

Moving onto your brakes, this is almost certainly a brake vacuum issue. I have seen similar before on Isuzu diesel engines which use an alternator mounted vacuum pump. Check the alternator belt and make sure its tight. If its loose then it could be slipping when wet and causing the vacuum to disappear. Do you notice a corresponding drop in electrical power at the same time the brake problem occurs?? Likewise, check the soundness of the hoses / pipework coming from the vac pump on the back of the alternator up to the brake servo. An outside bet is something amiss with the servo itself if water is getting into it somehow. It's highly unlikely to be a master or wheel cylinder issue as these usually cause a very soft pedal, not one that goes hard.

52paddy

shamwari wrote: »

I cant remember where the pollen filter is on those (whether its inside or outside) but if its outside I suggest replacing it as soon as you can because you could end up with water in the car in heavy rain.

Moving onto your brakes, this is almost certainly a brake vacuum issue. I have seen similar before on Isuzu diesel engines which use an alternator mounted vacuum pump. Check the alternator belt and make sure its tight. If its loose then it could be slipping when wet and causing the vacuum to disappear. Do you notice a corresponding drop in electrical power at the same time the brake problem occurs?? Likewise, check the soundness of the hoses / pipework coming from the vac pump on the back of the alternator up to the brake servo. An outside bet is something amiss with the servo itself if water is getting into it somehow. It's highly unlikely to be a master or wheel cylinder issue as these usually cause a very soft pedal, not one that goes hard.

It's been a while since I've revisited this thread but have some more info. I only see your post now by the way, otherwise I've had replied sooner. Sorry.

HEATER: The temperature is still not great. I did a test to see if it could be the thermostat. The engine temperature doesn't overheat so it's not stuck closed. I ran the car for a few minutes and felt the top hose from the thermostat to the radiator and, from what I can feel, it does change between luke-warm and considerably hot so I'd imagine the thermostat is functioning ok. I've yet to replace the pollen filter but will do so imminently. It's located near the bulkhead under the wiper assembly. Maybe the heater core is blocked also because the old pollen filter was jammed with ****e.

BRAKES: I never did get around to checking the vacuum pump because I did a quick inspection of the pads/discs to find they were the worst case of brake wear I'd ever seen! I don't know how they didn't just completely fail altogether! I replaced front discs and pads a couple of weeks ago and have since had no braking problems, even in rain.

POWER/SMOKE: I did an oil and oil filter change and threw in some injector cleaner. Took it for a lively spin on the M50 out towards Kilmack (N11) in 4th gear at 120kmh and it felt a million times better. I drove up "The Long Hill" and it was well able for 2nd gear and, at times, even 3rd gear so it had sorted the problem. The smoke was much less reduced also, just a bit of thick black up to 2000rpm or so. However, the following day, I felt a reduction in power again so wonder now if it could be an EGR valve that needs sorting? Or airflow sensor? The smoke has not been wild but there must be something happening in the system that could be dirtying the injectors...

Thanks for your help thus far. Almost there!