hi,

has anyone had experience changing the passenger side seat heat button in a '93 850. i've bought a new switch but can't figure out how to install it.
has anybody experimented by adding in rear seat heat?!!!

also i'm getting 280-290 miles to a full tank (19gallons i'd say). that's roughly 14-15miles/gallon. i'm screaming bloody murder! what should i change to improve this. i've put in two bottles of fuel injection cleaners, but no difference whatsoever!

there's been a overall oil leak around the engine. the oil cap seems to be leaking everytime i inspect it. it's tight enough though.

thanx!

Change the black rubber ring on the oil-cap itself... Even when it is tight, it can still leak under the pressure.

Where else does it leak...?

its easiest to remove the console, pop it out from the back to prevent damage to the surface.
rear heat can be added, there are universal seat heaters availible, but will require some work to install.
as for the mileage, full tune up. and check the o2 sensor. my s70 (sim engine, wieght) gets only about 18 in town. incorrectly gapped plugs are a biggie too on mileage with these engines.

the engine seems to have oil stain all over. but the only place where i can see it coming is from the engine oil cap area. i've attached a picture, as u can see how dirty the engine has become.

Does it consume oil in addition to the leak? If so, how much?

Have you done a compression test?

I had similar oil leaking problems with my 850. However, my gas mileage was in the 24-25 range even at the height of these problems. Perhaps you need to adjust the mixture or idle speed.

it doesn't consume oil too much so as to say it leaks, but i do see oil all over the engine. could be the result of a poorly cleaned engine over the years.

no i haven't done a compression test.

i will look into what you have said.

thanks!

Based on the photo, it doesn't look too good.

I would agree on the compression test. It lloks as if, the engine cap was reallly poor in condition to have the plate all messed in oil, like that.

The seat heat buttons are easy to install - they should simply pop out - i.e. they are only fixed with plastic clips. I haven't replaced mine but have removed them in the past to clean them, I used a watch makers screwdriver (v.small) and gently lifted the switches out - be careful with this approach as it is easy to damage the plastic around the switch and the switch itself.

The oil cap leak is common on all volvos (not just 850s) simply replace the cap's rubber seal - you can buy one from your volvo dealer for peanuts.

As for the fuel consumption things I can think are:

1) Injection system needs setting up correctly and have the throttle body cleaned.

2) Check the engine breather system - if poor quality oil has been used it will almost certainly be blocked with carbon deposits. An excellent oil to use to prevent blockages in the breather and to keep the engine internally clean is Esso Uniflow mineral oil. Don't be put off by it being mineral oil, I run it in all of my customers cars (engines and gearboxes) and never once had a problem. I have even run it in race cars! The only down side is that it requires changes every 6000miles and not 10000miles with this oil - so if run on this don't go by the service light!

3) Has the thermostat gone? although the temp gauge might show a reading, if it isn't dead centre and is dipping down slightly it means it is faulty and the ECU will try and run the car as if the engine is cold all the time using a richer fuel air mix

4) Finally, The timing might need checking. If it is too far advanced it will drink the old juice. With my own personal car I have spent a long time working on the timing and I feel I have a good balance of power and economy - its a 96 2.5 20v with 130k on the clock and did 37mpg (average) and still managed 145mph flat out over in Germany on a trip to the Nurburgring - not bad at all in my book! The other advantage of timing adjustment is the noise! get it right and the 20valve engines really sing!

Hope this all helps!

hi 850meister,

i replaced the heater button, it was quite easy, and which is why i've put the pics of how to do so.

i'll get these things checked.
i'm surprised that 850's can give upto 37mpg there!
the local dealer said it would be around 18-20mpg. i'd kill for your mileage!!!

when i went to a local non-volvo mechanic he said the piston rings need to be changed probably, since he opened the oil cap and there was engine oil bubbling up. he said that was a sign of bad rings. is that a possibility?

It is a possibility with higher mileage cars - I personally don't think the rings are worth replacing as it can cost a lot and doesn't always sort the problem. Most garages can do a "Leakage test to confirm how much gas leakage there is in each cylinder. - It requires fitting a tester to each cylinder, the tester runs on compressed air and calculates the amount of air leaking through each piston ring. I recently did a test on a 850 T5 (Turbo in the US) and even with 140k on the clock, that was reading around 10 -15% leakage on all 5 cylinders - very good for that mileage - (that is to say, no leakage would give a reading of 0% serious leakage would be 50%+). If it is piston leakage from worn rings, they do tend to burn quite a bit of oil off through the exhaust - so if it does use a bit of the golden stuff it prob is piston rings.

Again, returning to oil, If poor quality oil is being used that can cause leakage - The oil in the bores is really part of the "Seal". To give an example I serviced a Mercedes 190e 2.3-16 the other day which was suffering around 40% -50% leakage on all 4 cylinders, by simply replacing the oil with Esso the leakage dropped to around 20-30% on all cylinders. This obvously didn't completely cure the prob but goes to show just how important good oil is.

Essentially nearly all older cars will have some leakage and changing just the rings alone can cause more problems with wear in the bores etc.

I would try and live with the leakage and maybe explore other avenues, otherwise its going to be mega bucks to sort out.

N.B. - 37mpg was on a long run! That said around town I still get an average of 25mpg according to the trip comp. Needless to say at 145mph on the autobahn the instant consumption was reading around 2mpg Yikes!

Check the Vent box and all the hoses leading to and from it. Then Vent box may be clogged.

When was the last tune-up done? The spark plug wires have a date on them as long as they are OEM.