463 cooling system problems.
I have a 1991 300GE and when I bought it I was told that since the radiator semed new, the "well known overheating problem" had been dealt with. The heater always seemed pretty dismal, compared to the 1985 280GEL I have. After some work in low, the temperature soared, and a 15 minute traffic jam in really hot weather also produced excessive temperatures, so maybe the problem is still untreated.
Does anyoneknow what the problem was, and what the cure is?
Recently I have had a far from satisfactory lpg conversion, which has robbed the heater of almost all the hot water, and so I shall have to sort that out before winter, but I shall run the evaporator in series with the heater instead of in parallel.
What mpg should I be getting with 70mph on motorways, and 50ish elsewhere? I recorded 17mpg with a high hydrocarbon level in the exhaust, which has dropped to 11 on lpg!!!!!
Any hints as to the reason for high hydrocarbons in the exhaust? Recorded mileage 73000, and not in bad shape, new HT leads, distributor cap, rotor arm, and plugs.
CWDP,
Give the guys a little time....trust me, someone will know!!
Running a SWB 1991 300GE at the mo too. Fuel consumption MUCH better than your figures. Easily 20.
What is the reason for your dissatisfaction on LPG? Is it just the fuel consumption or something else? Recently LPG'd my wifes Merc Vaneo.... no discernible drop... just in fuel bills!!.
Check out the "Alternative Fuels" banner. Maybe something in there for you.
Cheers
Martin,
Thanks for reply. Presumably your 463 is auto too. My 1985 280 GEL did 13mpg on lpg, the 300 did 17.4 mpg on petrol before conversion measured over 4400 miles, and 11.5 on lpg over 1000 miles, with the odd bang!!
Presumably your Vaneo has a more sophisticated system than the diffuser arrangement in the air filter clamped onto the air intake. Maybe mine only does 12 on petrol with all this gubbins in the intake, I am going to experiment with this.
Have you ever had overheating problems with your 300?
Hi CWDP,
Both my 463's are Manual. 1 Diesel LWB and 1 Petrol SWB. I'd prefer them both to be auto, but there you go!!
No matter, your fuel consumption still seems on the high side.
Agreed the vaneo is a much more advanced system...should be for the £1600 it cost! :evil:
As for overheating, i'd prefer both to run a bit hotter!
Come on guys, give cwdp some answers to his problems!!
Have you ever had overheating problems with your 300?
had a 1994 G300 petrol in hotter climes (dubai!), and after about 4 years one summer stuck in a jam the needle went all the way to just below red...they took out the radiator and said it was mostly blocked..never been flushed, so it was replaced by a new one (and sold soon thereafter :))
Cooling problems>
First thing you need to check is the viscous coupling of the cooling fan. Get the engine to 100º C (the mark between your 80º and the red line) and then leave the engine idling and open the bonnet. Then rev the engine manually and observe the airflow coming from the fan. It should howl like a banshee and feel like you are in a wind tunnel! If it does, your radiator might be blocked.
My viscous fan packed up so for emergency i folded locking tads over so it blew max all the time but then changed it for a kenlow it was the best £120 I had spent, it revs better and quieter and added a few miles per gallon as well as pulled better
come late in this one. all 463 suffered from the problem of the radiators cores running horizontal, instead of vertical, any limescale that would normally fall to the bottom with vertical cores would lay in all of the cores in a horizontal rad. there are sceptics that say using type 30 MB antifrezze at 50% makes no difference but I cant vouch for either but I always used it in mine
My friend has a 463 300 petrol and both the rad and the viscous needed replacing. Also if you have aircon the electric fan will not work if the aircon has no gas, that was cured when the aircon was re-gassed. does it run hot on LPG only???. It could be your mixture is wrong, is it single or mulit point system you have???.
Have you drained the oil out of the LPG regulator recently, if the diaprahm gets contaminated then it wont work properly and not allow gas in so will run lean and make engine hotter. LPG can get contaminated with oil residue, but the supplier will say it doesn't, well it does. Running LPG always make the engine hotter anyway, because it burns hotter.
Is this tims old g??.
What plugs are you using, if there bosch then bin them, no good for LPG, use NGK, did you replace the HT leads with Merc ones, if not put back the old ones for a while. When using LPG it exaggerates any fault, including a short, if the leads are a made up lead then they could be suspect.
If its a single point system then you should be getting about 12-13 maximum on LPG at a steady 60 on my old LWB (Tims old one) I got 21MPG on petrol. round town 15MPG, live with it or buy a diesel. LPG conversions are hit and miss. Go to someone that only does LPG conversions and nothing else. Garages that do it as a side line are 80% waste of time.
Radiators definitely block up and at 100,000 miles or so need a new core or a complete swap. Not a big job and a recore just cost me £225 + VAT. Instantly runs a lot cooler.
My 1991 463 petrol auto does 17 mpg around town, for your info.
Also, at that sort of mileage if it is running a little rough at tickover and using more fuel than it should, get a new oxygen sensor. I removed the cat but the sensor is still in place (located just after the manifold) and essential for running at the correct mixture.
I say you have below listed problems.
1.viscous coupling is dead, put electrics. Pacet KPF1211( x 2) fan set up should work fine.
2.radiator most probably blocked
3.your heater matrix must be shot as well, because lpg does not affect heater performance
4.your lpg conversion (a bit complicated on 300 petrol, I have one as well with no probs.) might need an idle stabilizing control unit fitted, have you got one ?
5.lpg uses a bit more fuel than petrol. train yourself to drive at around 60-65 miles/hour max .
6. occasional bang usually means worn out valve seats at least on 1 cylinder. But what Peter perfect mentioned before are all valid precautions
i.e NGK spark plugs, proper HT leads Merc spec. etc etc
dont try to start and rev the car with LPG when the engine is cold.
good luck
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