Delica Canada | Mitsubishi Van Club

I recently had my thermostat replaced - as in around 2 weeks ago. It was installed locally and was brand new. Today, while at a different shop, the thermostat was removed and to everyone's surprise, there were two small holes drilled through the top of thermostat.

Can anyone explain why a perfectly good thermostat would be drilled out like this?

To make matters more puzzling, another van sitting near by also had a thermostat installed at the same local shop, but this one only had one hole drilled into it...

Any ideas?

quadzilla wrote:Can anyone explain why a perfectly good thermostat would be drilled out like this?

Pressure relief. When the thermostat is closed, and no coolant is flowing to the radiator, a small amount goes through the hole(s) to equalize the pressure. Otherwise, it could build up a vacuum and cause all kinds of problems.

At least that's what I remember! (And I'm never wrong, although occasionally I make mistrakes.)

If a brand new thermostat comes devoid of any holes or drilling instructions, why modify it? It would make the vehicle run at a lower temperature than it is supposed to. In my case, the temperature of the engine has increased slightly since replacing the thermostat with an unmodified one. If pressure relief was the intention, that still doesn't provide the rationale.

quadzilla wrote: the temperature of the engine has increased slightly .

the new thermostat you had put in might have been a hotter running thermostat, they do come in different Degree settings....

Yes - that's is understood, but what I don't get is why a thermostat would be deliberately drilled... Probably will never know. My guess is that this was an attempt to prolong the life of the worn rad hoses, which would have been accomplished by purposely drilling the thermostat so the van would run at a lower temperature. However, this is not a long-term solution and was never articulated to me by the mechanic that did the work, so as always, we non-mechanics are left to the devices of those of us who are mechanics... The lesson I learned here is that certain 'reputable' mechanics are a long way from that.

One thing for sure, the karma ghosts are preparing for battle...

Hi, what brand does your mechanic do put into your delica, did they put the lordco replacement thermosthat. if lordco replacement thermoshat there might be issue,
i did fix few of those as its not the rightone for this delica, in short it doesnot fit well that why the temperature is hot.
i usually used original mitsubishi thermosthat with orig. gasket, its cheap about $25.
if need help i have stock.
e-mail me or call me 604-720-6144
cheers;
Mardy

sweet plug Marty...



but for the guy with the drilled thermostat, why not just phone them and ask what his explination is? it could be to let the water through a little so you dont warp your $2200 to replace HEAD, it could be to help let air bubbles out so you dont end up vapor locked, They dont often spend alot of time moding new parts just to screw you over, some will use old parts and tell you its new since you cant really look inside, but if you go to a trused mechanic then with all the time they have left over I dont think they are trying to find ways to defeat your thermostat, and if they are then your not at a trusted mechanic and you have learned a leason, but I would phone or go in person to ask about it.
just my $0.02 worth

What was the temperature rating on the thermostat? That is far more important. I would ask the shop you bought it at if they drillled an additional hole and why. An additional hole would have a tendancy to lower your operating temperature a degree. If you don't like it close it up with a drop of solder or a stainless pop rivet. i doubt it's going to make any difference in your delicas operation. Hell it may even be a benefit in the summer.

the lazybrownfox.

Hi, its 82 degrees, its Original Mitsubishi thermosthat

Certainly some interesting thoughts. For starters, my question was posed more out of curiosity than trying to nail someone to a cross. My van was/is not running hot and it's not an issue of me 'liking' the holes or not - those holes aren't OEM, so it begged the question. The thermostat was one of many issues that are associated with a larger workmanship issue, and had the problems not been caught and repaired, would certainly have lead to serious engine issues in the not-so-distant future.

Also, I agree that reputable mechanics have better things to do than figure out ways to screw people over - they wouldn't be reputable if that was the case. In this case, though, I need to question the reputation given the other problems identified with the work that was done. The thermostat was the tip of the iceberg.

Well, once you're satisfied if your mechanic knows what he's doing or doesn't know than let us know who he/they are so nobody else ends up paying for poor service... thanks!

Hey Quadzilla
It's difficult being a new owner, dealing with the import problems, lack of maintenance in Japan and difficulties with garages and mechanics, not to mention the cash you laid out.

Hopefully the benefits of use, uniqueness of the delicas, and support from the rest of we fellow owners helps.

thelazybrownfox

Thanks thelazybrownfox (what font is that anyway? )

I have not become a jaded Delica owner because of this. My van will be getting a serious workout this year, so I am sure to benefit from all it has to offer. One thing for sure, I know where I won't be going for future service.

Hmm, just had a thought this morning. Bound to happen when the temp is -25

I've got a lower rad hose coolant heater. Someone on this forum a while ago warned that the thermostat would block the circulation and the coolant in the rad could boil over. So one possibility is to drill small hole in thermostat to allow coolant flow.

Comments anyone?

Hi, I dont think it will block the circulaion, when the antifreeze reach to a certain temperature if its too hot it will open the thermosthat,same as when the engine is running goes to certain temp & thermosthat will open.
thermosthat is near the water pump, so the heat could circulate in the lower rad hose toward you radiator & to the block under.
this is the way they design to fit this lower radiator heater.
hope this help,
Cheers:
Mardy