Why you should use a thermostat

I will not hide my opinion: USE ONE.

There is some interesting fresh discussion on this topic on the shoptalkforums website:

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I humbly ask you to read my reply from today (Dec.29) to understand how widely it effects the way your engine operates. It's not just temperature in itself that is a concern.

Aussiebug explained the operation of the cooling flaps pretty well too. It is relevant to the discussion. Here's my old page on flaps:

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Jan

Reply to
Jan
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"Jan" schreef in bericht news: snipped-for-privacy@mid.individual.net...

Usefull info, thank you! I'm in the same situation as John... summer ride. Only mine is from before '70. I'm told not to use one because IF the thermostat fails the flaps will be closed and the engine won't cool at all.

Reading your (and many more) post on this topic makes me gona put them on my next engine..

Keep those ideas coming.. :) Roger

Reply to
bug '59

The problem isn't why to use one but how to get them if you need one now that they're no longer available.

I'm fortunate that I have one on my Bug but when it goes, I guess I'm screwed...

T> I will not hide my opinion: USE ONE.

Reply to
Anthony W

I have a thermostat that is well compressed (less than 3 cm) but then it doesn't expand until its it gets very hot water! (actually boiling=100 C. or so) and after 3 sec. it compresses it self back to close position. I assumed its not good because it written on it its 65-70 c. so it suppose to expand at colder temp than direct boiling water ... any suggestions? also - I was wondering.. it looks like when it is fully open - it expands like 2 Cm at the most (less than 1 inch) and when i play with the THERMOSTAT rod with my hand it feels and looks as it needs more than a 2 cm travel (up and down) so I'm afraid if I put the thermostat I will limit the cooling flaps range (maybe it willnot be full open etc.) I have another thermostat but its a bit more open from the begining (its open 3.5 cm) so it got left to open like only 1 cm!!! is that better than leave the system always open (thats the ststus right now - even though i feel the spring is getting weak)

thanks nachche

ps - how do i add pictures?

Jan wrote:

Reply to
nachche

the only way a thermostat fails, is if it gets punctured. In that case, it's design makes it expand, and stay expanded forever. This forces the flaps OPEN, to FULL COOLING. It's a safety feature.

Without the thermostat, there's still a spring pulling the flaps open.

Jan

Reply to
Jan

Reply to
nachche

Go figure.. You see, it is a MUST to keep ramva alive. Thanks Jan,

Roger

Reply to
bug '59

You don't, Jan would chew your arsh(Or nibble your bottom, if you prefer .) Posting a link is ok though..

J.

Reply to
Berg

Reply to
Dennis

In a cold climate(like Norway) you can freeze an engine overheating with the thermostat locked open, simply because you are overcooling the cylinders. What happens is the pistons expand warming up, while the cylinders stay "narrow" as in small dia because of the lack of heat(because of overcooling).

I have experienced this first hand with a 30ps engine(36SAE in America), yes, different thermostat design, but fully doable with the latter design as well.

Not common, but doable..

Takes the engine a lot longer to heat up even if it does not "freeze", hence higher mechanical wear..

J.

Reply to
Berg

Everyone's entitled to have their own opinion, as long as they all acknowledge that I'm right and they are poopy-heads.

:D

Yup. If nothing else, have the flaps in place and jammed open.

Poopy-head.

;P

Ah! You raise a very good point. The tin pieces all need to be there, and fit tight, for the system to be able to pressurize and direct the air where it is needed.

I'm not talking about dramatic breakdowns or engines blowing up, it's more subtle than that, but still bad for the engine due to more rapid wear and all the other mechanical problems I explained in my reply in the shoptalkforums. You must not have read that. Go do so, to understand what happens when you allow the engine to warm up too slow, or never reach normal operating temperature. (No thermostat). People complain about head leaks and pulled head studs, but I bet you 90% of them are not running a thermostat, and/or do not have all of the cooling components in place.

It is not a matter of going from cold to fully warmed up, from position

0 to position 1. It is about controlled transition, a series of time and temp related events that are designed to happen in overlapping sequences, so that the very different metals involved would all expand just as the factory intended. If one heats up faster OR SLOWER than normal, you will have problems.

I kept extras around for my customers who couldn't locat5e them on their own, plus a few for my priuvate stash ;)

I can't say I love them, but once you have them COMPLETELY dialled in to match your engine, you really do not need anything else, and they work FINE. I don't have a single flat spot with mine, never have since I learned to properly tune them. Sadly, it requires more work, knowledge and time than your average engine builder wants to put in it.

MIneral for break-in, after that it's your choice. Some synthetics may not work well, so educate yourself on what brand and type and weight works best for the aircooled engine. Monitoring oil temperatures is one form of feedback, but it really does not give you all the data you need.

The BIGGEST advantage of synthetics is their resistance to breaking down (thinning) with age. HOWEVER... in our aircooled VW's, we cannot take full advantage of this, because we need to change our oil more often anyway, because it gets DIRTY. Modern cars have closed loop ventilation, all filtered, but our engines are open to the athmosphere and dirt, plus soot and other combustion residue conbtaminate the oil in a heartbeat.

There is nothing a mineral oil cannot do, that synthetics can, that would make one "need" to use synthetics. The greatest benefit is something we cannot use. (at every oil change, you would be throwing away perfectly good synthetic oil just because it got dirty).

Full flow filtration is one step in the riught direction in combating this, but you also need to close the case off from the athmosphere, and that requires a bit more work. On top of it all, most of us run a carbureted induction system, and there is a lot of combustion byproducts and residue that gets into the oil, past the piston rings. Modern enginmes burn fuel cleaner.

I do not build performance engines without FF. Even daily drivers from me get FF, unless originality must be preserved for show judging or classic registration purposes.

Put two engines side by side, run them through identical conditions, weather, temp, load, maintenance routines.... for 10-20 years. The one without a thermostat will show all kinds of irritating little problems. Oil leaks being one that hasn't been mentioned yet. (uneven, uncontrolled thermal expansion and all that bull)

Unfortunately, you generally can't "see anything being wrong" instantly.

Jan

Reply to
Jan

i used to have quite a collection of expensive ported and polished heads that were cracked severely....the cause? cold air blowing over the outside while the heat from combustion was trying to expand the metal....something always has to give....

Reply to
Joey Tribiani

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Dear Jan,

Pretty much a waste of time, eh?

After leading the horse to water, the rest of the job is up to the horse :-)

-Bob Hoover

PS -- Leading up to Christmas there were a lot of deliveries here at the house and a lot of the drivers were temporary hires, unfamiliar with the flatter, easier to negotiate back driveway. So I'd show them. One of them got all excited when he saw my bus parked back of the shop, asked if it still ran. "Every day," I told him. Or nearly so; certainly several times a week.

"Oh man! Why don' you feex it up?"

"Like what?"

"Jew know... Lower it.. Get you some chrome rims. Nice paint job."

I thought about saying something then decided it would be wasted breath. He was in his thirties, couple of tats, probably lucky to have found some part-time work. His idea of life and how to live it was clearly different from my own. So I just smiled, wished him Merry Christmas. - rsh

Reply to
BobHoover

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Hehe...

well, if one or two people reading that are serious about their engine project, and decide to take my advice.. it was worth it.

Those who choose to ignore it and think I'm a paranoid freak full of reindeer doo, will eventually be supporting their local acvw repair shop and pouring more money into supporting the parts businesses.. so everyone wins and the vw lives on :)

:)

Me, I like almost anything and everything you can do to/with/in an aircooled vw. So my goal was to get one for every occasion and purpose, each built for satisfying just one need and want. I can appreciate a meticulously restored stocker as much as a tastefully customized rat-rod. Then of course, I like to travel so a bus was a must.... :D

Sadly, all that remains is a low budget ratty custom-wannabe convertible . But I like it, it runs strong and I BUILT IT :)

Jan

Reply to
Jan

Although your opening temperture does not sound right, the thermostat should expand to at least 46mm, so you are in the right zone, in that respect.

The rod connects to a 'looped' arm on the right had flaps which can become accidentally bent (by rough handling), causing a decrease or an increase in the full open position. Obviously the flaps can not open past the 'stops' but it means that either the flaps don't open fully or they get to 'full open' at a lower temperature.

BTW, Jan, I support your comments fully. There is far more to the VW air cooling system than most would ever realise!

Reply to
pjmsvw

Thank you :)

Funny how something so simple can be so complicated... then you change one little detail, and everything starts collapsing.

jan

Reply to
Jan

Alas, that is the fallacy lurking behind the curtain.

Eventually the rolling wreck, having been 'improved' for the umpteenth time, is acquired by owner number umpteen-and-one who finds the cost of repairing the incredible accumulation of 'unimportant' problems is beyond his budget. The machine may get passed along but in many cases it simply sits in the weeds for a year or two before going into the crusher.

With bad maintenance nobody wins. The VW does not live on.

-Bob

Reply to
BobHoover

thanx but to check the looped arm I have to tear down all fan area (dog house?) and since i cant realy measure when it will be full close/open without all the system in place i 'm afraid it will not do its job prperly. first thing I'm wating to get a better thermostat (that opens at 65-70 C=2E ) and then check the range it pushes the rod I'm realy waiting to put that on because like Jan i think this is very important. If I cant find a good thermostat or if the travel it gives will not be enugh - U'm thinking of putting a manual push/pull cable to the ROD so i can close the flaps when starting the engine and the push the cable (rod) to open the flaps my indication will be either 5 minutes from startup or my temp gauge what do you say?

snipped-for-privacy@hotmail.com =EB=FA=E1:

Reply to
nachche

thanx but to check the looped arm I have to tear down all fan area (dog house?) and since i cant realy measure when it will be full close/open without all the system in place i 'm afraid it will not do its job prperly. first thing I'm wating to get a better thermostat (that opens at 65-70 C. ) and then check the range it pushes the rod I'm realy waiting to put that on because like Jan i think this is very important. If I cant find a good thermostat or if the travel it gives will not be enugh - U'm thinking of putting a manual push/pull cable to the ROD so i can close the flaps when starting the engine and the push the cable (rod) to open the flaps my indication will be either 5 minutes from startup or my temp gauge

i say you are asking for a meltdown if you make it a manual system......the bracket for the thermostat is adjustable for a reason....adjust it so the flaps are full open at full extension....

Reply to
Joey Tribiani

Yes, that sounds like the most sensible thing to do now. Worry about the rest of it at a later date when you have time to look at it properly.

Reply to
PJMS

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