water pump or thermostat? - Page 2

Jul 16th, 2006, 19:26

Well We'll get a new stat at some point ......... I agree its a odd fix ....... But just happy to have the thing running normally

Derek UK · Jul 20th, 2006, 11:08

Andrew, the disc on the bottom of your new thermostat will correctly block off the bypass tube in the head. This balances the flow of hot/cold coolant. Not all engines seem to have this tube, maybe introduced at a certain date.
As your bottom rad hose was badly blocked it would seem likely that the bottom part of the rad was in a similar state. Back flushing may get some of it out but some of the tubes are still likely to be blocked. I'd have a go with one of the off the shelf remedies like Rad-Flush to start with if you don't want to take the rad out again at this time. It might help. Check the rad cap and expansion bottle cap if you have it. Even if all seems OK check to see if the rad is hot all over. If still significantly cooler at the bottom, budget for having your rad recored. Not too pricey and I'm sure someone on the list can recommend a "good deal" close to you, where ever you are.
Stay cool!
Derek

Andrew (UK) · Jul 20th, 2006, 21:59

Hi Derek,
That's the first I have heard of any B18/B20 engines not having that tube in the head.
The cooling system seems to be working OK now. I did swap the water pump for peace of mind. I then filled the system as carefully as I could and went for a run. I only filled the reservoir bottle to a little over the minimum line. At the end of the run the level in the bottle had risen a couple of inches and the radiator was hot top and bottom. So I would cautiously say that all seems to be OK now.

Thanks everyone,
Andrew

Jul 20th, 2006, 11:08	#12
Derek UK VOC Member Last Online: Yesterday 14:22 Join Date: Jul 2006 Location: Chatham	Water pump or thermostat Andrew, the disc on the bottom of your new thermostat will correctly block off the bypass tube in the head. This balances the flow of hot/cold coolant. Not all engines seem to have this tube, maybe introduced at a certain date. As your bottom rad hose was badly blocked it would seem likely that the bottom part of the rad was in a similar state. Back flushing may get some of it out but some of the tubes are still likely to be blocked. I'd have a go with one of the off the shelf remedies like Rad-Flush to start with if you don't want to take the rad out again at this time. It might help. Check the rad cap and expansion bottle cap if you have it. Even if all seems OK check to see if the rad is hot all over. If still significantly cooler at the bottom, budget for having your rad recored. Not too pricey and I'm sure someone on the list can recommend a "good deal" close to you, where ever you are. Stay cool! Derek

Jul 16th, 2006, 19:26	#11
J..M Guest Location:	Well We'll get a new stat at some point ......... I agree its a odd fix ....... But just happy to have the thing running normally

Jul 20th, 2006, 21:59	#13
Andrew (UK) VOC Member Last Online: Dec 3rd, 2021 08:39 Join Date: Jan 1970 Location: Sutton, near Ely	Hi Derek, That's the first I have heard of any B18/B20 engines not having that tube in the head. The cooling system seems to be working OK now. I did swap the water pump for peace of mind. I then filled the system as carefully as I could and went for a run. I only filled the reservoir bottle to a little over the minimum line. At the end of the run the level in the bottle had risen a couple of inches and the radiator was hot top and bottom. So I would cautiously say that all seems to be OK now. Thanks everyone, Andrew

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