Thread: RV8 - Thermostat Temps

Fully open at 88C.
If you have a 14CUX in a D1 then you must have 88C or the enrichment will not turn off fully in winter.

The golden rule with an RV8 is NEVER let it get over say 105C . That is why the aircon fan comes on at 102 C.

Regards PhilipA

Thanks Philip - when the thermostat is fully open - compared the cross section area of top radiator hose - the amount of water that can get through a fully open thermostat is relatively low - so I assume that with a 74c thermostat it just means it opens earlier than say a 82c thermostat but because it does restrict flow ultimately the engine does not actually run cooler, it just takes longer to warm up.

Only have a manual choke so no auto enrichening.

Cheers

Garry

Thanks Philip - when the thermostat is fully open - compared the cross section area of top radiator hose - the amount of water that can get through a fully open thermostat is relatively low - so I assume that with a 74c thermostat it just means it opens earlier than say a 82c thermostat but because it does restrict flow ultimately the engine does not actually run cooler, it just takes longer to warm up.

Only have a manual choke so no auto enrichening.

No the engine should operate near to the fully open temperature of the thermostat when warmed up except when climbing a big hill or maybe crawling in traffic on a hot day. At cruise it should run at no more than the fully open temperature.

If it climbs above the fully open temperature then there is a problem with a blocked radiator .(or maybe heads leaking gases into the v)

In winter it may run under the fully open temperature maybe 82c or whatever.

When you stop the engine on an RRC they will heat soak usually up to maybe 95C with an 88C thermostat.

The viscous fan usually cuts in at about 94C.


While different as they run cool when under light load my diesel TD5 usually runs at about 83-85 C with a 88C thermostat and new radiator..
Regards PhilipA
BTW the restricted hole is there for a reason, to slow down the speed of the coolant through the radiator so that it has more time to cool.

Originally Posted by PhilipA

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In winter it may run under the fully open temperature maybe 82c or whatever.

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While different as they run cool when under light load my diesel TD5 usually runs at about 83-85 C with a 88C thermostat and new radiator..
Regards PhilipA
BTW the restricted hole is there for a reason, to slow down the speed of the coolant through the radiator so that it has more time to cool.

Yeah, too low thermostat has issues in cold climates. On my '79, the heater worked really well in normal conditions, never lacked heat and Melb suburbs can get below 0° regularly, and around town heater worked very well.
But on a drive one time heading out to central desert country, going through Beaufort(western Vic) must have got well into the -5° ambient range, and I had a 72°C thermostat fitted at the time. As I was on highway, wayy too much cool air keeping engine running very cold, and nothing but cold air out the heater.
Stopped at a truck stop to do something about it, had a foam camp mat thing for camping. Cut it up and shoved some between bonnet and bullbar to totally enclose the radiator grille. Helped to get heater warm again at least, and ran that way till Murray Bridge.
I also ran it with twin thermo fans with good results for many years/miles. Thermos, set to about 85-88°, never came on, on this drive with grille covered up.

Going by my experience now with my D1 Tdi, I'd estimate that the coolant running through the heater matrix on that night must have been in the 50°C range, even tho the thermostat is supposed to be 72°C. The car interior itself wasn't that cold just wouldn't keep the screen demisted, but ex did appreciate the added warmth henceforth.

In summer, see similar-ish temps to Philip in my Tdi now with it's 88°C thermostat. In Wintery temperatures tho, I see more like high 70's on the whole, once warmed. I usually run with the viscous off between May-Aug with no ill effects, even in traffic around Melb. It may climb up to high 80's maybe 90 if I push harder sometimes, but I usually don't push harder.

If you have manual choke, I'd say between 78 would be good for around town driving, and 82 for highway travel as long as the rad is in good nic(which is another story on my '79) if you drive this thing in very cold ambient(ie. ACT!).

The other thing I recently found with thermostats is the way the different brands run in every day operation.
My Tdi had a Waxstat rated at 88°C stamped on it. I bought two Trico thermostats, one 78 and one 88. Fitted the 88.
All tested to see how they each work. Trico definitely much more responsive than the Waxstat brand. Could be coz they were new tho. But the Waxstat is very sluggish to open, even at 100°C it took forever(minutes) to be fully open, which still wasn't as open as the Trico stats.
The Waxstat responded quickly to close up with added cold water, just slow to open.
With the boiling water testing, the 88 Trico started to open according to thermometer in the lower 80° range(say 83) it varied but ballpark is enough.

Originally Posted by 101RRS

With the RV8 there are a range of temp thermostats available - ranging from just over 70c up to about 90c or so.

What are the advantages/disadvantages of using lower temp thermostat vs higher temp thermostats in the RV8.

Also what is the recommended temp for a 3.5?

Thanks

Garry

The later the RV8 the hotter they are MADE to run,,, Like,, run this hot or I will shoot you,,, not the made In japan sort of made...
The only reason for a 96deg thermostat is emmisions.
Its like dancing on a knifes edge,, while drunk, and carrying a broken carton of beer
can you do it? sure,, but not for long...
and the result is a disaster..

88 will be fine for a 3.5

This is mine.

Runs cool as the proverbial cucumber. 84 to 88 range most of the time.

Cheers

Originally Posted by ozscott

This is mine.

Runs cool as the proverbial cucumber. 84 to 88 range most of the time.

Cheers

That is the same as mine - is slow to open in the vehicle but tests Ok on the stove. As mentioned a new Trico might be the go.

Thanks to everyone for the input.

Garry

Just adding my 0.02,

I agree with Pedro, the later V8’s handle higher temps very well. I frequently see 110deg on my 4.6 in summer, that has never alarmed me, although I do try to keep it below. I have read and heard that this is to do with emissions in the later Rover V8’s and “improves fuel consumption”. The thermostat appears to start opening at 90deg on mine, fully open at 95deg, but I would be hesitant to go over 100deg in an early Rover V8.

Cheers
Keithy