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mirsini
mirsini

Posted: Wed Apr 08, 2009 9:57am

Post Subject: temperature gauge/water pipe

Hello, The water supply pipe from the engine to the hot water immersion tank broke off. I fixed it but the temperature needle stays at 95. Whereas prior to "fixing it" the gauge would reach 95 then drop back to 80, is there a fault with it sticking at 95. The engine ran ok, did not overheat during a two hour trip. Is it OK ? Also can i use the black fuel pipe instead of radiator hose ? for the water pipe engine to calorifier. ? Many thanks for your help.

Tony-B
Tony-B

Posted: Wed Apr 08, 2009 10:28am

Post Subject: temperature gauge/water pipe

Dear Johno, This sounds to me as if the engine cooling thermostat was a bit reluctant to close down once it had opened and probably the overheating shook it up a bit so as long as it does not boil it should be fine. However I am a bit concerned about the 95 degrees, I would expect it to be closes to 85. Make sure the skin tank is clear of air because this could be a symptom of air in the skin tank reducing its cooling effect. It would not hurt to change the thermostat for one rated at no more than 82 degrees. I do not understand the bit about fuel hose because fuel hose normally only has a 1/4 or 5/16" bore where as the calorifier hose is usually a minimum of 1/2" bore. If it fits however and is rated to withstand close to boiling water temperature then it should be absolutely fine. Tony Brooks

mirsini
mirsini

Posted: Wed Apr 08, 2009 11:43am

Post Subject: temperature gauge/water pipe

I am very grateful for your help. I will do what you say. Thanks johno

mirsini
mirsini

Posted: Wed Apr 08, 2009 11:49am

Post Subject: temperature gauge/water pipe

Dear Tony, further to previous question. The engine has stood over night and is cold but the temperature gauge reads 65, even though i have not started it up since yesterday. Sorry, what is "skin tank"? not a phrase ive heard of. Thanks again. johno

Tony-B
Tony-B

Posted: Wed Apr 08, 2009 6:36pm

Post Subject: temperature gauge/water pipe

First the temperature problem. Locate the temperature sender unit high up on the engine and disconnect the cable. The gauge should drop to zero. If it does it indicates that the sender unit probably requires replacing but note that sender units are matched to gauges. They cone in UK or US specifications. If the reading stays at 65 then check for burnt/chaffed through cables between the gauge and sender. If you find none make sure the earth/negative connection on the gauge is in good order then consider the gauge might be faulty. My money is on the sender though. A skin tank is a cooling tank welded to the side or bottom of a metal boat which will have two large cooling pipes connected to it. Without knowing what type of boat and cooling system you have I assumed this related to a standard narrow-boat. Tony Brooks

mirsini
mirsini

Posted: Fri Apr 10, 2009 10:41am

Post Subject: temperature gauge/water pipe

Dear Tony, Thanks for your prompt reply and your time.I will check over easter weekend. Very grateful for your help. Johno

mirsini
mirsini

Posted: Fri Apr 10, 2009 5:37pm

Post Subject: temperature gauge/water pipe

Dear Tony, I checked the sender unit, disconnected it the gauge did not drop to zero. There was nothing wrong with the cable. I cant see an earth wire on the gauge there is just a centre wire through the brass nodule screwed to the gauge. Where is the thermostat? engine is BMC (captain) 1.5. 1973. I ran the engine, the gauge already at 45 when cold, went up to 98 then back down to 90 after a while. The water in the calorifier normally gets very hot but when turned on taps it was luke warm. I want to change the thermostat but cant figure out where it is. Also where is the best place to buy new Thermo and gasket / A lot of questions, but thanks for your help, i am grateful. johno

Tony-B
Tony-B

Posted: Fri Apr 10, 2009 6:06pm

Post Subject: temperature gauge/water pipe

Dear Johno, Unless someone has fitted cannibalised car parts your gauge - the actual clock thing - should have three connections on the back. One 12v supply from the battery, one negative "earth" connection and one that is connected to the sender unit. I can not make any sense out of what you tell me about the connections so can you send me a digi-pic of the back of the gauge with its connections to Tony@TB-training.co.uk. What you describe almost sounds like the connection on the sender unit. Your engine probably has two sender units. One about half way down the block and towards the back on the right hand side. This is the oil pressure warning lamp switch or sender. Ignore this one. The temperature sender is still on the right but right at the front of the cylinder head. Immediately above this is a (sort of) domed triangular housing held down with three nuts. This is the thermostat housing. I would expect to buy the thermostats and a "universal" gasket that needs cutting to suit your engine from any decent motor factors like Unipart. However it you do not want a thermostat rated at 82 degrees or more you might have to go to a marine supplier like Calcutt boats or ASAP supplies. They may be able to supply a gasket specific for your engine. For goodness sake download and print out the manual for your engine from the engines page of the Calcutt boats website. That should be far easier to follow than just words on the forum. Please keep me informed and I think we need to sort out the gauge before spending too much money. Tony Brooks

Tony-B
Tony-B

Posted: Sat Apr 11, 2009 9:29am

Post Subject: temperature gauge/water pipe

I have been pondering your description of the gauge and have just had a horrible thought. It could describe a very old capillary gauge where the sender unit is a bulb containing alcohol permanently attached to the gauge by a long, thin tube, usually spiral wound with a single stiff wire. If this is the case then it was broken when it failed to drop when cold. It certainly is now if you managed to get that tube off the sender. If this sounds like your setup I would suggest that a call to ASAP supplies will get you a suitable electric gauge kit. Tony Brooks

mirsini
mirsini

Posted: Wed Apr 15, 2009 8:54am

Post Subject: temperature gauge/water pipe

Dear Tony, Thanks again for your help. I took boat up the river, at full speed, the gauge reached 95 then drops back to 88. It did not overheat. I tried to change Thermostat but once the three nuts were released, i could not free the housing as it seems to be a complete unit (water filler head etc). As it is not overheating is it ok to carry on using engine ? Have tried to send you photo but using "DONGLE" is a bit hit an miss. But overall water remains at proper level and is not over heating ?? Would like to change thermostat but the housing will not shift.?? (BMC 1.5 Captain) Thanks for your help johno

mirsini
mirsini

Posted: Wed Apr 15, 2009 8:56am

Post Subject: temperature gauge/water pipe

Tony: PS> The gauge when engine cold is at 50 start position. Johno

Tony-B
Tony-B

Posted: Wed Apr 15, 2009 2:01pm

Post Subject: temperature gauge/water pipe

Johno, If the temperature gauge gos to its lowest position when the engine is cold that is fine. The temperature readings you give seem to indicate the thermostat is a bit reluctant to open but it is still OK, just keep and eye on the temperature and do not think that reading is accurate because it is not. The thermostat housings do corrode onto the studs on the newer engines that use an alloy housing - really old ones had cast iron! To move it you need lots of soaking with a proper penetrating oil (Plusgas), taps/whacks around the stud holes with a hammer, tapping nor levering upwards and sometimes a chisel between the housing and cylinder head, but if you need to do that you will probably need a new housing. A blowlamp around the stud holes helps as well. Tony Brooks

mirsini
mirsini

Posted: Wed Apr 15, 2009 3:02pm

Post Subject: temperature gauge/water pipe

Tony, I am very grateful for all the help you have given. You took a load off my mind. Thanks again. Johno

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