Thermostat opening temp

[Ffirg 005]

Motorway driving in these colder temperatures the Griff has been running at an indicated 60 degrees on the gauge. Previous posts on this suggest this is too cold and over time will cause accelerated engine wear so I'd like to know if it's a problem or not.

I did the start-from-cold test and the top radiator steel pipe is stone cold for 5 minutes and then rapidly gets hot, as it should. But the temp gauge at this point has barely lifted off it's stop - well below the first indicator for 50 degrees.

The pipe is too hot to touch for more than a second when the thermostat opens which I would have thought is about right.. Maybe the one in the cabin is just reading too cold? I don't have another temp gauge to check the reading... should I get it checked or am I worrying about nothing?

Don

[david beer]

The senders quite often go high resistance and therefore the guages read low. What temp do you see when the fans cut in? If its in the high 80s or low 90s then i would say the water stat is too low or faulty.

[simpo two]

On B-roads today (typically 40-60mph) my average running temp was little more than 70 deg. No fans required. However on summer days it's 80 (90 in traffic until fans cut in), and on that very hot day one Sunday it was 90 all the time, even at 80mph. So I guess it's just one of those things.

But why does my BMW run at EXACTLY same temp in all weathers and conditions? What does BMW do that TVR can't?

[david beer]

I know this has been done to death,but, my Griff hardly moves between winter or summer. A 88 water stat means at least 88 in winter and the fans mean a max of around 90. Having(eg) a 72 water stat and an 92 otter gives the "TVR Swing". Whilst i understand the "get the stat open early, cuz we only have fans at 92" it can be done just like all other grown up cars.Stand back and wait for it!

[simpo two]

david beer said:

Having(eg) a 72 water stat and an 92 otter gives the "TVR Swing".

Why would anyone fit a 72 water stat then?

[shpub]

simpo two said:

But why does my BMW run at EXACTLY same temp in all weathers and conditions? What does BMW do that TVR can't?

They fit duff temperature guages...

[shpub]

If the guage is accurate.... and it is showing 60 degrees on a run then irrespective of what stat is fitted, it will be closed. The lower winter temps are more to do with the colder air flow than anything else.

Big treatise on this in the bible.

[tovey]

today my temp was at 70 untill i hit traffic then rose to 80 i noticed only one fan kicked in, it is a 1998 500 does the other fan kick in at a higher temp.

[david beer]

Both fans should come on at the same time, unless someone has done a mod. The connectors near the fans can be a little troublesome, otherwise its a fuse or faulty relay.

[david beer]

Why would anyone fit a 72 water stat then?[/quote]

Early opening water stats start the cooling early but mean a cold drive in the winter. As for BMW temp readings, every other car i have had has had a stable temp guage. I have two rover v8s, the other one in a rangie and its guage doesnt budge also. I understand that TVR themselves fit 72 stats, so it cant be bad for an engine !! Personally i like my Griff with a stable temp.

[smb]

david beer said:

Why would anyone fit a 72 water stat then?

Early opening water stats start the cooling early but mean a cold drive in the winter. As for BMW temp readings, every other car i have had has had a stable temp guage. I have two rover v8s, the other one in a rangie and its guage doesnt budge also. I understand that TVR themselves fit 72 stats, so it cant be bad for an engine !! Personally i like my Griff with a stable temp.[/quote]

So what parts would you recommend in terms of stat's and fan operating temps. I assume you used one of your mod's for this?

[Boosted LS1]

It sounds to me like to much air flow through the rad so it's being over cooled.

[Ffirg 005]

shpub said:

If the guage is accurate.... and it is showing 60 degrees on a run then irrespective of what stat is fitted, it will be closed. The lower winter temps are more to do with the colder air flow than anything else. Big treatise on this in the bible.

Thanks Steve and others for your comments. I did consult the bible before posting and there is a lot of information about the system that was useful for me, but I didn't feel it said much about "how cold is too cold".

The Bible does say that at cold temperatures fuel consumption is higher and the chart on p141 suggests that 60 degrees is at the lower end of normal operating temperatures. I'm getting 60 degrees in the cold-ish conditions this week and if my gauge is correct then my thermostat is opening at less than 50 degrees, so when we get sub-zero temperatures I could be running at well below 60 and I'm still not sure whether to be worried about that. The bible doesn't mention engine wear being caused by cold running, though this was something I think I read on another thread, and would seem reasonable.

I don't say any of this as a criticism of the Bible BTW Steve - just explaining why I posted this question.

David - in answer to the question about top-end temperatures, never goes above 92 degrees, even idling in traffic on hot summer days. With rising temperature fans come on at about 75.

I guess I really need to whip out the thermostat and do the boiling water test with a thermometer to see what parameters its working to (procedure well covered in the bible )

>> Edited by Ffirg 005 on Sunday 16th November 22:51

[johno]

I have put both a 72 Thermostat and corresponding Otter switch into the Griffith to help it in hotter temp's and it now never gets over 80 in any conditions ...

Last year going to Auxerre with standard Thermo and otter switch we ran on the motorway at night in France at reasonable pace (very late) at 55 degrees ...

I do not believe for a second the engine was running at that teamp ... it couldn't have been due to the speed, just the cold air affecting resistances to cause silly readings ..

At the moment with the colder stat I am seeing 60 - 65 degrees on motorway cruising at speed. The thermostat is not open at this temp and therefore I do not waoory about.

I may change to a hotter stat, but I really cannot see why it would make any difference at all ...

[ro_butler]

shpub said:

simpo two said: But why does my BMW run at EXACTLY same temp in all weathers and conditions? What does BMW do that TVR can't? They fit duff temperature guages...

Not quite, but if they are anything like most mainstream ones they will sit in the middle of their range almost irrespective of the coolant temp. They only move to the red zone when the engine is about to overheat, which is a little late.

I personally prefer to know if something is wrong a little sooner, and feel that temp gauges that don't move just give you false comfort.

[david beer]

johno said:

Last year going to Auxerre with standard Thermo and otter switch we ran on the motorway at night in France at reasonable pace (very late) at 55 degrees ... I do not believe for a second the engine was running at that teamp ... it couldn't have been due to the speed, just the cold air affecting resistances to cause silly readings .. At the moment with the colder stat I am seeing 60 - 65 degrees on motorway cruising at speed. The thermostat is not open at this temp and therefore I do not waoory about. I may change to a hotter stat, but I really cannot see why it would make any difference at all ...

Johno,
why not try the spare sender on top of the head, its actaully in the head rather than being like the original,exposed to cold air. It will only prove that it the original is getting cold though !

[GreenV8S]

david beer said:

As for BMW temp readings, every other car i have had has had a stable temp guage. I have two rover v8s, the other one in a rangie and its guage doesnt budge also.

Normal mass production cars normally have a non-linear temp gauge that reads the normal temperature the moment the engine starts to warm up, and stays there until it is just about to overheat. The other reason your Rangy doesn't overheat is it is designed to pull a two ton load out of death valley at 20 mph on the hottest day of the year. The fan alone draws several horsepower. Overall it has about 20 times more cooling than you will ever need in normal driving in UK weather. The TVR cooling system is a lot more marginal and the fans are wimps by comparision.

[johno]

Cheers David, I'll give it a go .....