Thermostat or No Thermostat? - That is the question

Pizzer11 · Post by **Pizzer11** » Wed Jan 23, 2008 11:57 am

Hi again,

For those who have not been following my previous post about odd temperature readings.....

http://www.igmaynard.co.uk/bongo/forum/ ... hp?t=17850

.....my mechanic has concluded that my recently installed, refurbished engine does not have a thermostat; however, the temperature gauge is working accurately (he is however checking that this is the case). Therfore, he says I basically have 3 options to proceed with.....

(1) Continue to run the engine without a thermostat - My mechanic says he has run in to a few bongos with overheating problems that relate to faulty thermostats (I assume he feels there is something inherently wrong with bongo thermostats as opposed to thermostats themselves). He says this would be like an insurance policy against my engine being a victim of a thermostat related overheating and provided I can live with the heaters taking a while to warm up, it won't do the engine any harm.

(2) Install a thermostat - This is my favoured option. Engines I assume are supposed to have one and I bought one in advance which will arrive at my mechanic's today. Assuming the temperature gauge is working fine and I install a temp. sensor like the one Missfixit did, surely I can pick up the warning signs of an engine overheating should the thermostat go faulty. A colleague informed me that part of the thermostat's job is to keep the engine at an optimum temperation for efficiency (is this true?) and that if it runs at a cooler temp., it may be using more fuel than it should. Also, I'm about to start a 7-week spell boarding in the French Alps so I reckon I'll be quite keen to have the heaters warmed up ASAP.

(3) Install a thermostat, but drill a hole through it - or something like that my mechanic said. Means the thermostat won't operate exactly how it should, but in case it does become faulty, it won't fully block the coolant flow and therefore reduces the chance of overheating. Sure I read this being done by someone on another thread but I can't find it anymore. Anyone out there run there bongo with a thermostat modified like this?

Thanks again for your advise in advance.

paul9 · Post by **paul9** » Wed Jan 23, 2008 12:39 pm

go with option 2,removing a thermostat is only giving the wrong impression that all is well,and in some cases can do more harm than good.
a reconditioned engine should really have had a new one put in anyway as a precaution.

francophile1947 · Post by **francophile1947** » Wed Jan 23, 2008 12:44 pm

Definitely option 2. A cold engine uses more fuel and most engine wear happens whilst your engine is cold.

flippa · Post by **flippa** » Wed Jan 23, 2008 1:13 pm

mine is running with a thermostat with at least one hole drilled through it ,this was done by someone who knew nowt about bongo's at the time i didnt either....i overheated before and after this was done ....funny enough pizzer i had recently been thinking about replacing it for a new one...good luck

haydn callow · Post by **haydn callow** » Wed Jan 23, 2008 1:13 pm

Yep !!! option 2

dandywarhol · Post by **dandywarhol** » Wed Jan 23, 2008 5:33 pm

If your "mechanic" is suggesting option 1 then change the "mechanic"!

No 'stat or a butchered 'stat is disguising a problem with the system - my guess from a distance is a partially choked radiator.

Pizzer11 · Post by **Pizzer11** » Wed Jan 23, 2008 6:12 pm

In addition to the Refurbished Engine, I replaced the radiator with a Brand New Genuine Mazda Bongo radiator and replaced all the hoses with new Silicon Hoses stocked by Flippa. He's pretty certain that the Refurbished Engine didn't come with a Thermostat. Will know soon.

Either way, I asked him to install the new thermostat and I'll look at getting the alarms and sensors done to.

I have nothing but praise for Mick and his band at MD Motors. He did plenty of work on my old engine in a hope to save it, consulted Bell Hill Motors for advice, and when it didn't resolve the issue he shouldered the cost. He then resisted the temptation to overcharge me for the engine replacement labour and apart from what appears to be an over sight on his part with this thermostat (or is he simply not wrong to assume the engine would come with a thermostat), the engine runs fine.

I feel he simply let me know that he has concerns with Bongo thermostats.

Ralph · Post by **Ralph** » Wed Jan 23, 2008 6:42 pm

A thermostat should not need a hole drilling in it,
they well the ones I have looked at usually have
a small one with a little widget in it that rattles about
and keeps this small hole clear, but I wounder if
drilling a bigger one helps the system to self bleed
if it lets the air out of the head and out via the
top hose? that would explain why you seem to come
across Bongos with a hole drilled, once enough air
is out of the system to allow the water pump to fill
with water the system should bleed it's self pretty
quick as long as you top it up.
Enough of these ramblings probably wrong anyway.

dandywarhol · Post by **dandywarhol** » Wed Jan 23, 2008 7:55 pm

Sorry if I slagged off your mechanic Pizzer but option 1 really isn't an option and a good mechanic should know that!

The "widget" Ralph is a jiggle pin and that's what it's there for - to allow a system to bleed - the "float" in the pin then closes the hole when coolant gets to it. I don't know if the Bongo 'stat has one or not

Ralph · Post by **Ralph** » Wed Jan 23, 2008 8:22 pm

A Jiggle pin never knew it's real name, love it.

Pizzer11 · Post by **Pizzer11** » Wed Jan 23, 2008 8:29 pm

No worries at all DandylWarhol

. Just don't want Mick to get any negative publicity after all he's done for me. I was recommended him from the Bongomaster and he's in our database of recommended servicers(?). I can vouch for one thing, after what he's been through with my Bongo he's certainly learnt a whole lot!!

The Great Pretender · Post by **The Great Pretender** » Wed Jan 23, 2008 11:51 pm

Option 4.

Put the thermostat where it needs to be to protect the cylinder head from overheating and damage.
On the outlet from the head.