The Triumph Dolomite Club - Discussion Forum

A couple of questions from a relative newbie to Dollys....

It's a late '76 Sprint with a rebuilt engine inside that last 2000 miles or so. The radiator hadn't been changed so I've fitted an Alicool rad to the car - http://www.alicool.co.uk/rad-triumph.html - and it came with a fan switch which operates 92 - 87C (electric fan). The car has a new 82C thermostat fitted.

My question is what is the "normal" operating temperature for the engine coolant and do people think that the fan switch is correct temperature or should it be higher (as it cuts in a lot)?

Many thanks!

Steve

They do vary a bit but it should sit in the middle of the temp gauge when its warmed up if the voltage stabiliser is working ok.

It also drives the fuel gauge so a dodgy reading fuel gauge is an indication your temp gauge may not be accurate. On my Spit the stab is intermittently faulty so it reads hot and low fuel. I'm not sure if a Dolly is wired the same way, but I suspect so.

Anyway you want 10.2 V out of the stabiliser by the fuse box....light green wire is out.

Then the fan should cut in about a needle width before the 3/4 hot mark. If it goes up to this or beyond something is wrong.

The fan in and out temps sound about right.

Jonners

Thanks Jonners.

I wanted some reassurance re temps as mine sits in the middle of the gauge running along at anything over 40mph, but quite soon rises above half way when you have to slow down a lot or running for any distance in town. The fan does indeed cut in between 1/2 and 3/4 on the gauge and with the fan running it never reaches the 3/4 line even on the hottest days. It's just it seems the fan is cutting in and out quite a lot more than I have been used to with other classics....including a Stag I used to own.

I have recently replaced the temp sender and just this week replaced the Voltage stabiliser as well (just in case!), so we'll see this weekend when it's on a run what occurs.

It had been running like a bag of spanners as well which might not help the temperature - it's running a Piper mild fast road cam and I don't think it's ever been set up right. Luckily my brother works in a garage with a compete rolling road set up so I've just made use of that and now it has the correct needles and mixture setting it's achieving about 135 BHP + at the flywheel - but I've not driven it yet to see if that's mad any difference to the temp. But at least it should go better now!

Thanks again
Steve

Steve, not all temperature senders are the same. I would use one from Robsport for the TR7, should give the proper output. I found the Land Rover ones that Rimmer and others used to supply gave a slightly higher reading and were much more sensitive.

Sounds interesting.

Mine runs a STR91 equivalent at 106ATDC and new needles did make a big difference...

If you had the standard sprint needles the later ones are weak anyway which would make it run hot. Ignition timing and advance are also
crucial for good temps...

Jonners

OK so I have XJX back a few weeks now from the rolling road and she's running a treat - plenty of get up and go, and the temperature is definitely much better. The fan still cuts in around town, but the temp drops again very readily once you get moving.

I have new problem though.....

Oil from the slot just below the water pump cover.....a pretty constant trickle when the engine is running and certainly enough to make everything below there oil covered. Nice.

I take it this is probably the water pump oil seal? Seeing as the pump was rebuilt with the engine about 18 months ago - and has only done 1000-1500 miles since it's a bit worrying. Too much pressure in the system somewhere now it's going well?

Any thoughts welcome....

Are you sure its oil and not anti freeze?

Its far more common for the top water seal to go than the oil seal below it.

Jonners

GTS290N wrote: ↑Fri Sep 01, 2017 6:59 am Steve, not all temperature senders are the same. I would use one from Robsport for the TR7, should give the proper output. I found the Land Rover ones that Rimmer and others used to supply gave a slightly higher reading and were much more sensitive.

Absolutely; this incompatability of gauge/ sender / voltage regulator is a problem.
I have done a mini investigation into this and found that with the engine running for 2 minutes to stabilise the voltage regulator and the temperature sender replaced by a 68 ohm resistor, and also allowed to stabilise for 2 mins, the gauge should read exactly 1/2 scale at "N".
( See a future edition of D.M. for details ).

Jonners - definitely oil. Am currently in middle of rebuild of water pump but unfortunately the rebuild kit I bought had the oil seal missing....more than a bit annoying when I discovered that in the middle of the job on Sat afternoon....so that's the first phone call on Monday morning....

The working theory as to why the oil seal might have gone - following a discussion with my brother who set the car up on the rolling road for me - is that he needed to put restrictors in the breather tubes that feed the carbs from the rocker cover to get the mixture right whilst setting it up (several different needle combinations were tried - not forgetting it's running a fast road cam) - he thinks that MAYBE this has created increased pressure in the crank case - POSSIBLY enough to force oil past the water pump oil seal. I can see where he is coming from, because it did not leak oil (or indeed use any) before the rolling road set up.

So when it's all back together - I can't take out the restrictors, but I can create restricted short stubby inlet pipes to the carbs so I don't upset the running, and vent the engine breather to atmosphere.
Well, it's worth a shot....