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Jul 14, 2014 12:58 pm
Jul 14, 2014 12:58 pm
Subject: Re: 4.5 litre engine problems and upgrades
I am not a very experienced long time Lagonda man (only ten years now) but engineer and I think much of these overheating problem (see also the M45 stuck in London traffic on the way to "the one show", equipped with electric fan) is due to restrictions in water circulation. I think this goes in line with most of the previous posts on this topic.
I had this on my V12. The car would boil at low revs e.g. driving on the highway and then get into stop and go in a traffic jamm or at the end of a mountain climb. The water temperature at this point still beeing acceptable. Electric fan or new radiator does not help much in this case because the water is still cooled well but does not reach the hot areas at sufficient rate. The reasons are:
1. Problems in the design at first (was still ok when the car was new)
2. Water pump with less performance due to corroded rotor
3. Corroded water passages plus lime deposit
The cure is: solve the above 3 problems, at least the last 2, especially if you do a complete engine overhaul. Or put an electric water pump as temporary cure for the problem. I did the last (in series to the existing water pump), I switch it on when I anticipate it will be needed (slowing down after strong going, traffic jams) and it works. And if I forget to switch it on then I have the boiling, quite reproducably.
Things would be different if the true water temperature (measured with a correctly reading device) goes to high, then I would go for radiator clean, electric fan, new readiator.
I prefer water as coolant, when it boils=evaporates it cools extremely well and this boiling indicates the problem early. I will not try waterless coolants.
I am not a very experienced long time Lagonda man (only ten years now) but engineer and I think much of these overheating problem (see also the M45 stuck in London traffic on the way to "the one show", equipped with electric fan) is due to restrictions in water circulation. I think this goes in line with most of the previous posts on this topic.
I had this on my V12. The car would boil at low revs e.g. driving on the highway and then get into stop and go in a traffic jamm or at the end of a mountain climb. The water temperature at this point still beeing acceptable. Electric fan or new radiator does not help much in this case because the water is still cooled well but does not reach the hot areas at sufficient rate. The reasons are:
1. Problems in the design at first (was still ok when the car was new)
2. Water pump with less performance due to corroded rotor
3. Corroded water passages plus lime deposit
The cure is: solve the above 3 problems, at least the last 2, especially if you do a complete engine overhaul. Or put an electric water pump as temporary cure for the problem. I did the last (in series to the existing water pump), I switch it on when I anticipate it will be needed (slowing down after strong going, traffic jams) and it works. And if I forget to switch it on then I have the boiling, quite reproducably.
Things would be different if the true water temperature (measured with a correctly reading device) goes to high, then I would go for radiator clean, electric fan, new readiator.
I prefer water as coolant, when it boils=evaporates it cools extremely well and this boiling indicates the problem early. I will not try waterless coolants.