3 holes in k series thermostat - what would the effect be?

[Garf]

Currently changing my hoses to silicone and performing the K series mod from Sep 2012 LF - I also removed the thermostat to see 1) what temp it operated at and 2) if it had a hole in it (and what size).

It was a 86 degC and had, to my surprise, 3 x 4mm holes in it!!   The car is 1995 and was raced back then - I understand some race ones removed the thermostat (i'm the 4th owner but this could still be original one to keep race temp down).

Decided to fit new QH 82 degC and with only 1 x 2mm hole.

My question is what would the effect be of so many holes?

I'm expecting that it would have taken a long time for the engine to come up to temp (maybe it did but I had no reference.....) and in winter maybe not hot enough.

I haven't driven it for a few months (other winter project work on suspension/frame) but actually recall a good but high running temp (can't be sure how long it took to reach it) but that it would quickly heat up further once stopped and cooling & fan cutting in later than I would like (since checked the old thermostat and it actually opened at 94 degC about when the fan cut in so not an ideal balance).  On the plus side no airlocks! 

[Jonathan Kay]

I'm expecting that it would have taken a long time for the engine to come up to temp (maybe it did but I had no reference.....) and in winter maybe not hot enough.

Yes, but hard to predict how big those effects would be.

Can you face doing a back to back comparison? Blinded if you can find an accomplice.

Jonathan

PS: I think we hear more tales of overcooling than in the past.

[John Vine]

...what would the effect be of so many holes?

I would say there would be a significant risk of overcooling, as those holes would be the equivalent of a stat that didn't close properly.  IMHO, the single 2mm hole you have will prove fine (its sole job is to avoid airlocks while filling with coolant).

JV

[Baz Hemsley]

You have reduced the pressure so it will boil quicker. My xflo boiled very quickly when I first had it. When I checked the water I noticed the t'stat missing. put one in and has not boiled since...... that's my logic for what it's worth.

[John Vine]

You have reduced the pressure...

I don't understand why that should be.  Could you explain?

JV

[Toby S]

When I bought my 1400 k supersport - I couldn't get normal operating temperature much above 65, other than in the height of summer where it went to around 70 during spirited road use, which is miles too cool.

Found that the thermostat, had been removed (I suspected it was either that or the thermostat was jammed open).

Fitted a standard Rover 88 degree thermostat and it now sits at a nice 82/83 all day long - depending on ambient temperature (other than in traffic when fan kicks in at a squeak over 90 degrees and quickly gets the temperature down to 88 before cutting out.

Admittedly. I only use for spirited road use not racing, but it seems to keep a safe temperature range 82- 90 in road conditions.

I'd guess the more holes in the thermostat, the lower operating temperature would be maintained, but I wouldn't fancy a temperature below 80 when revving through to 7600.