• Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

MGB Temp sender issues

Stewart

Darth Vader
Country flag
Offline
Blew a head gasket on my 75 and had the head checked over by the machine shop which tanked the head magnafluxed it, skimmed it and fixed a few valves that were leaking. Head went back on runs great but the temperature gauge reads low 1/2 way between the C and the N. Previously ran dead nuts in the center. After 200 miles it dies completely and verified dead by my ohm meter.

Replace with new red topped b710 one from moss gauge works again however when the engine is at room temp the needle now goes to 1/3 of the way to N. With the engine running it goes 4/5ths of the way to the H while IR show the engine at 170 175F.

Changed it out again with another one at room temp its a needle or so above the C and it's a bit better at 1/2 way between the N and the H.

At this point I switched to the Standard Motor Products TS233 sender and at room temp its now where I would expect it to be with the ignition on however it's still reading high at 1/3 or the way between N and H at 175 degrees.

Ohm red top 450 at 75f 90 at 175f
Ohm TS233 540 at 75f 120 at 175F

Any Ideas on what's going on? Gas gauge is working normally and is accurate.
 

JPSmit

Moderator
Staff member
Silver
Country flag
Offline
Might be as simple as reproduction senders being calbrated differently. Can you test them in a pot of boiling water? Or alternately buy an infra-red thermometer and check engine temp.
 

DrEntropy

Great Pumpkin
Platinum
Country flag
Offline
Put a potentiometer in line with it and "tune" the resistance to match the normal position of the gauge when temp is at 170°~175°f. Ohm the pot at the appropriate position and get an equivalent resistor to put in line with the wire behind the gauge.

:thumbsup:
 
OP
Stewart

Stewart

Darth Vader
Country flag
Offline
Took a shot before messing with resistors and put in the wrong sender from '77 on. Well guess what its now reading dead on right go figure. At least I know the whole system is in great shape as I went through everything including checking the calibration of the temp gauge.
 
Similar threads
Thread starter Title Forum Replies Date
vette Threads for the Water Temp Sender Austin Healey 6
Mink TR4/4A Temp gauge/sender question Triumph 15
bigjones Testing Temp Sender Spridgets 5
pipercollins Running Temp, Guage, Sender Questions Triumph 11
L Spitfire temp sender for spit 1500 Triumph 7
Rob_P Temp Sender MG 3
Bob Claffie Temp sender thread Austin Healey 18
I temp gauge or sender? Triumph 3
JPSmit next dismantle question - water temp sender Spridgets 10
RJS TR4/4A Smiths Oil Temp Gauge Triumph 11
G Smith's temp gauge repair Restoration & Tools 4
MikeAH100M High Temp Engine Miss Austin Healey 2
RJS TR4/4A TR4A Temp Gauge Scale Triumph 6
Martinld123 Problems with my BN2 Temp Gauge reading Austin Healey 13
shadowfever Water temp Spridgets 9
Govtslug TR6 Coolant Temp Q Triumph 4
EWD TR6 Temp Gauge - 74 TR6 Triumph 11
Editor_Reid Water Temp Gauge Austin Healey 5
H TR4/4A 67 tr4a runs rough and losses power when hot but not over normal temp Triumph 14
J TR6 73 TR6 Temp Gauge Wiring Question Triumph 6
Rut Bugeye 1275 temp probe placement. Spridgets 8
B For Sale Triumph Tr3 Fuel gauge Temp gauge Oil pressure gauge, speedometer tachometer Triumph Classifieds 0
S TR2/3/3A temp gauge sealer Triumph 7
W Electrics, fuel system, under bonnet temp. Austin Healey 3
S TR2/3/3A removing the temp gauge needle Triumph 5
T TR2/3/3A Where is best spot to check temp with infrared thermometer? Triumph 17
DugMoney Need Advice - Moving Temp Gauge Sensor 1275 Spridgets 3
M Proper running temp for 1275 Spridgets 28
JFS TR2/3/3A Radiator fan temp probe Triumph 3
D TR2/3/3A tr3 temp guage capillary tube thread size Triumph 3
JFS TR2/3/3A Temp Sensor Removal Triumph 6
S TR4/4A Temp guage problem Triumph 5
R Capillary tube temp gauge Austin Healey 7
R TR2/3/3A TR3A tired temp gauge Triumph 5
RickPA Water temp gauge reads low Austin Healey 6
F TR2/3/3A Water Temp Triumph 10
R water temp bulb loose Austin Healey 27
C Wanted Sunbeam Alpine 1, II Water Temp Electrical sending unit.[Or one that will work] Other British Classifieds 1
Superwrench Oil Pressure/ Water temp Gauge Austin Healey 17
K TR2/3/3A Temp gauge capillary tube routing? Triumph 11
Gundy Temp gauge on Mk3 Midget Spridgets 4
M water temp gauge Spridgets 7
A TR4/4A Tr4A temp gauge doesn't work Triumph 19
Sopwith_Camel temp Jaguar 8
T TR4/4A How hot at radiator neck when temp gauge is reading innthe middle Triumph 6
Got_All_4 TR2/3/3A Need a temp glass Triumph 11
B Temp gauge capillary tube Austin Healey 3
P Temp. Probe for 1275 with Bugeye Radiator? Spridgets 21
Jim_Gruber Temp sensor wire spring re attachment to probe Spridgets 3
KVH TR4/4A Infrared Thermometer for Radiator Temp Triumph 6

Similar threads

Top