Drilling thermostats?

Author
Discussion

Howitzer

Original Poster:

2,840 posts

217 months

Tuesday 20th May 2008
quotequote all
I believe my 500E Mercedes (Same engine as SL500 etc etc) has a thermostat which closes when the temperature reaches the required temp, reverse flow or something?

Now as the engine is so well packed into the engine bay cooling systems can prove troublesome. I did at one time want a custom radiator made but after seeing some posts on here and similar websites I don't think this is the right action to take.

So will drilling a thermostat of this type work in the same way as a regular type? I've got it all arse about face in my head and for some reason am struggling to get a clear picture if it will or not.

I understand that this will give me slower warm up times (It's very very fast as it is anyway) but i'm hoping the slightly better flow, while still controled (Unlike when the stat is removed completely) will help lower temps at lower speeds.



Dave!

GreenV8S

30,252 posts

285 months

Tuesday 20th May 2008
quotequote all
Is that a picture of your stat? It would appear to be closed (i.e. just like a conventional stat).

The usual reasons for drilling holes in stats are to improve bleeding, or to soften the response when the stat initially cracks open to reduce thermal transients. Do you have any reason to think that you need either of these changes?

Edited by GreenV8S on Tuesday 20th May 13:33

Howitzer

Original Poster:

2,840 posts

217 months

Tuesday 20th May 2008
quotequote all
It is supposedly one of the stat in my engine, I've yet to drain the cooling system or make any mods to mine though.

Bleeding and warm up are fine, this was mentioned on an american car site and is supposed to give cooler running temps when driving around town, it currently will sit at around 100°C which is what it was designed to do but if I could keep the temp down a little it would be good.

I was hoping for a concise yes, but if there is doubt to its effectiveness then i'll leave it as is, it's certainly not an engine I want to overheat.

Dave!

smckeown

303 posts

246 months

Tuesday 20th May 2008
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I thought drilling stats was a false economy, as it takes lonbger for your car t get up to temperature. I've always reduced temps by running stats that open at a lower temp and using quality coolant and water wetter. I successfully reduced my temps by about 12 deg C recently using these methods.

GreenV8S

30,252 posts

285 months

Tuesday 20th May 2008
quotequote all
Drilling the stat won't make any difference to maximum cooling when the stat is fully open, so it's not a cure for overheating problems.

Howitzer

Original Poster:

2,840 posts

217 months

Tuesday 20th May 2008
quotequote all
Yeah this was to try and get a bit more flow.

Just a new stat and good quality coolant it is then.

Cheers chaps.

Dave!

Howitzer

Original Poster:

2,840 posts

217 months

Tuesday 20th May 2008
quotequote all
Yeah this was to try and get a bit more flow.

Just a new stat and good quality coolant it is then.

Cheers chaps.

Dave!

shalmaneser

5,937 posts

196 months

Wednesday 21st May 2008
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How old is your rad? I changed to an ally one (from a steel) and running temp dropped significantly!

Nissens do a range of high quality ally rads for pretty good prices. Might be worth a go?

Love the 500E's by the way. Russian Mafia cars! (in a good way!)

Howitzer

Original Poster:

2,840 posts

217 months

Wednesday 21st May 2008
quotequote all
There is a group buy on the 500E.com website but i'm not entirely sure that it would be much better than a standard one as it's a very nicely made rad anyway.

Like you say though it's now 17 years old and could be full of crud inside for all I know, I did a coolant change 2 years ago and backflushed it but hardly anything came out.

It is definitely a Mafia car, Toad of Toad hall haha, it'll never be sold! Nice to know more people appreciate it.

Dave!

Otto

738 posts

217 months

Thursday 22nd May 2008
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Whoever has drilled the stat in the pic has made a right balls up of it. The smaller disc should NOT be drilled - when fully open, this is needed to block off the bypass hole - i.e. STOP the coolant just circulating around the engine without passing through the radiator. With the holes in the smaller disc, a portion of water will now bypass the radiator when the thermostat is fully open, essentially reducing the cooling performance.

A few holes in the larger disc CAN increase the amount of flow going through the radiator, although it's a very small improvement. Making sure the cooling system is performaing as it should would serve you much better (although not as cheap!) - i.e. water pump - are all blades of the impeller intact? Radiator not partially blocked etc etc.

Howitzer

Original Poster:

2,840 posts

217 months

Thursday 22nd May 2008
quotequote all
Yeah the blades are all ok, when these fail it will boil in minutes apparently. The clutch on the fan is ok, the electric fans come on when they should do but i've only had them both on once at full speed as this wont happen till 115°C from what I can gather.

Dave!