MG MGB and MGB GT Tech Talk
My recently purchased '73 MGB has new Moss radiator, new 180 degree thermostat, temp sending unit is new. Now the gauge shows almost hot after just a few miles. Doesn't boil over and the engine doesn't seem hot, but the gauge indicates it's maxed out almost. Any ideas on the problem would be appreciated.I assume the gauge is ok, don't these rarely fail?
Thanks for your input!
Steve
There have been some defective senders sold recently based on the number of heat related threads I have seen. I would verify the water temperature with a probe type thermometer.
Clifton
Welcome to the Experience!
Steve, verify that both top and bottom rad hoses are the same temperature after warm up. This will give you an indication that the thermostat is opening. I believe you could OHM the sender but sorry, I dont have the specs.
Rob
Gauge is probably ok, but the problem is with the electrical sender. Just replace to an all mechanical gauge and be done with it. The electric gauges are shite.
you are stuck having to verify a temp value you cannot without buying something.
the temp gage is not really very accurate. at full hot it is supposed to be 212 degrees , but who knows ?
Altho a new sender, it could actually be the wrong one. There were two used and if the previous owner bought the wrong one it would give you bad readings.
Finding out an approx temp for your coolant is not that difficult, altho it may mean you have to buy a thermometer to test it. A reasonably accurate one can be bought at most auto stores or Harbor Freight for a reasonable price. You may find the info on this webpage of interest to you, http://www.cibolas7.net/12299.html .
Also there have been previous discussions on this BBS about this and related topics so you might want to rummage through the recent archives here. Just do a search using the search button at the top of this page.
A simple "candy" thermometer made by "Taylor" is all you need. You can get them in most grocery stores and hardware store. See attached pic.
I have always wondered if there can be a polarity issue when one connects the wire to the gage???
If the car originally came with the electric instruments, there shouldn't be a polarity issue regardless.
If I recall correctly, Dennis, MG went to electrical instruments for Temp and Oil press the same year (68) as they switched polarity. Prior to that, there might be a problem if the previous mechanical gauges have been swapped out for newer or aftermarket units. Dave Dubois would probably know for sure.
The sender has to be matched with the gauge. I'm not sure when the change-over was but when I put a 68 engine in my 79 the gauge maxed out, once I swapped out the sender for the correct one the gauge read fine again.