Rover 420Di poor heater

A mile? Thats normal. Could be the thermostat that's lazy.

If it was normal then there wouldn't be anything wrong with the thermostat. The heater's definitely subnormal, but I wondered whether the thermostat could be improved too.

I would consider it normal for an old car, but everything else I've been in recently seems to warm up (according to the gauge, not just the heater) considerably quicker, including a couple of other diesels, and even an elderly Volvo 740 with its big iron lump with loads of open space under the bonnet and a huge fan bolted on the front which you can hear whooshing away even when it's cold. Nowadays you can expect to see gauge movement and feel something from the heater after a few hundred yards.

A car taking a mile for the guage to start to show anything is perfectly normal.

However if the thermostat isn't closing properly then the water doesn't fully reach operating temp and thus the heater will be crap.

Yup agreed. Both the 306 and Focus take about a mile to register anything on the temp gauge, and a further mile or so to reach normal operating temp.

Dan

Most diesels take "ages" to warm up compared to petrol engined models, because they are much more efficient and waste less energy as heat!

Don't suppose it's your first diesel? They're always slower to get the heater going, and perhaps also the engine in your car isn't of the latest generation.

In this weather it obviously takes longer, but the point is that it is definitely slower than most other cars of its age. I haven't paid excruciatingly close attention, but I reckon others would be fully warmed up before the gauge on ours starts showing anything. Since catalysts were introduced manufacturers started making engines that warmed up as quickly as possible. I'm just trying to establish whether the Rover L-series wasn't designed so well in this respect or if I might have a dodgy thermostat. I would just change it, but I've got a long term illness and the Haynes manual talks about getting underneath for better access, so I'm not confident about tackling it myself, especially if I want the heater flushed at the same time. If a garage or mobile mechanic will do it for under £50 and it makes a big improvement I'd consider it money well spent, but I'd be pissed off it didn't make much difference.

A partially closing thermostat will just delay it reaching full temperature unless it's also fully opening early. This does reach full temperature, at least according to the gauge. The heater takes longer still to get reasonably warm, so that could be caused by the hot water taking a long time to work its way through a partially blocked matrix.

There is some "fur" in the expansion bottle, does that suggest a general build up, or is a certain amount perfectly normal?

That's a good point except that in that case they should have correspondingly smaller capacity cooling systems, so if you don't have the heater on (which I avoid until it's at least partially warmed up) it shouldn't make any difference. It's the design of the cooling system etc that's important.

The Pug 106D we had before took a long time to warm up too (it didn't have a temperature gauge, but the heater took ages), but I'm sure the Cavalier 1.7D before that was much quicker - about the only thing that was quick about it apart from oil consumption. Also my dad made some comment that his 405 TD would be well on the way to warmed up by now at a point when the Rover was still stone cold.

We've had 6 diesels in the family so far. Apart from the Peugeot 106 I didn't notice the others being much worse than our petrol cars, if anything the Cavalier warmed up quicker than most of them.

AOL goes one better. If it's minimised and you click "Close" on its taskbar icon, it opens.

addresses.

I guess you could feel the engine outlet hose and heater inlet hose and compare the temperature. If the heater hose is somewhat cooler than the engine hose then I guess that it could point to a heater matrix problem.

I would also check that the heater control valve is operating correctly. Get someone to sit in the car and turn the heater dial whilst you watch the valve assembly in the engine bay.

HTH

I was wondering about trying that.

I didn't realise it would be visible. The knob definitely feels as if it's connected to something mechanical that's working smoothly enough IYSWIM.

addresses.

My diesel engined car warms up very quickly but that is because it has an electric heater as well as the radiator worked off the engine.

It takes mine 2 or 3 miles for the water temperature to reach what I'd call warmed up, but it has the electric heater to fill in before that happens.

-- James

addresses.

It's a direct injection diesel engine, it's thermal efficiency means it takes time to warm up.

If you want an engine that warms up quickly get a petrol and put up with the poor fuel economy year round.

-- James

The size of the radiator is unimportant, they can't really be too big, only too small. If you put too large a radiator on a car the thermostat will compensate for it keeping the engine at it's correct temperature, where as too small a radiator and the engine would overheat.

All of the above are / were indirect engines, yours is direct injection, hence more efficient and colder.

-- James

Sure you don't mean a diesel burning heater?

The car's alternator output isn't likely to be more than 1 kilowatt or so, and that wouldn't go far towards heating a car on a cold day.

My car has a 120 watt alternator as standard. It has to be able to cope with the 750W electric heater, plus glow plugs with afterglow, heated rear screen, heated door mirrors headlights, foglights etc. Apparently the electric heater turns itself off / down when other stuff is on so that it doesn't overstress the electrical systems. Diesel engined cars come with rather heavier electrics than your average petrol engined car ;)

-- James

I presume you mean amps? But so have many these days.

Wonder why they didn't just fit a diesel burning heater - you could then have that set to come on with a time switch and come out to a warm car in the morning. They're common in cold countries. They use very little current.

Wot - no electric seat and steering column adjustment?

The only real difference is they are more difficult to spin over due to the high compression ratio, and usually take more churning than a petrol engine before firing. Everything else is the same.

About midway along the bulkhead near the bottom (IYSWIM). You'll see the feed and return hoses for the heater matrix disappearing through the bulkhead, the valve is located adjacent and one of the hoses will be connected to it. Hope that makes sense.

I didn't mean the radiator so much as the amount of water in the engine block jackets. If it doesn't need so much cooling it can have less water.

That's plausible, but I'm surprised it makes that much difference.