Hole in thermostat
Thread Starter
Junior Member
Joined: Dec 2000
Posts: 66
Likes: 0
From: Ontario, CA
Hole in thermostat
If I drill a small hole in the thermostat will this help cooling or will too much antifreeze flow through? I have a 91RS with a 350, stock water pump and a BECOOL radiator and 180* stat. It still will hit 240* on 100* days driving with the A/C on in traffic. I was wondering if a hole in the stat might help?
TGO Supporter
Joined: Aug 1999
Posts: 14,811
Likes: 1
From: Jackson County
drilling a 1/8 to 3/16 hole is common thing to do with a SBC t-stat, shouldn't hurt a thing.
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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM
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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM
Member
Joined: Jun 2001
Posts: 470
Likes: 0
From: Lakeland, Florida
Car: 91 RS Convertible
Engine: 305 TBI
Transmission: 700R4
One hole is not going to make that much difference. IMO
You're running at 240° with ac in traffic and 100° temps.
Sounds normal to me!
I've got a 305 and it runs 220° with ac in traffic in 110° weather.
I have heard about the drilling process though. Look in the threads here under the cooling issues.
There's a post with pictures and everything regarding drilling of the T-stat.
They mention drilling 4 holes.
Haven't tried it yet, but it's worth the time and a $2.99 T-stat to see if it helps.
Also try some watter wetter in the rad. It may be the reason you're running @ 240° and I'm running @ 220° under the same conditions.
But it could also be the simple fact my engine is smaller than yours.
Enter.... ( I think I can.... I think I can.....)
Run with the big boys.
Ok, Maybe NOT!
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91 Mystic Teal RS Convertible (1 of 5,000+ made in '91)
Stock 305 TBI, Auto Trans, Stock Rear End
Stereo
Nakamichi CD-35z, Infinity Kappa Series 4x6 & 5 1/4" speakers, Fosgate 12" sub in a custom box, 200watt amp for the sub.
Future Mods & Add Ons
You're running at 240° with ac in traffic and 100° temps.
Sounds normal to me!
I've got a 305 and it runs 220° with ac in traffic in 110° weather.
I have heard about the drilling process though. Look in the threads here under the cooling issues.
There's a post with pictures and everything regarding drilling of the T-stat.
They mention drilling 4 holes.
Haven't tried it yet, but it's worth the time and a $2.99 T-stat to see if it helps.
Also try some watter wetter in the rad. It may be the reason you're running @ 240° and I'm running @ 220° under the same conditions.
But it could also be the simple fact my engine is smaller than yours.
Enter.... ( I think I can.... I think I can.....)
Run with the big boys.Ok, Maybe NOT!
------------------
91 Mystic Teal RS Convertible (1 of 5,000+ made in '91)
Stock 305 TBI, Auto Trans, Stock Rear End
Stereo
Nakamichi CD-35z, Infinity Kappa Series 4x6 & 5 1/4" speakers, Fosgate 12" sub in a custom box, 200watt amp for the sub.
Future Mods & Add Ons
- Infinity Basslink
- Hooker Headers
- 3" Exhaust using Flowmaster 80 series muffler
- MSD Ignition
- K&N Filter
- Some Suspension Improvements
Senior Member
Joined: Aug 2001
Posts: 814
Likes: 2
From: San Jose, CA, USA
Car: 88 IROC-Z - original owner!
Engine: LB9 with K&Ns, MSD, Foil, Taylor
Transmission: WC T-5
Axle/Gears: BW 9-bolt, 3.45 posi
I followed the advice of the local gurus and drilled 3 holes in my new t-stat. Ends up being one hole too many. Now I have to replace it again. If it's a cool night, the engine won't come up to temperature with 3 holes. This is on an 88 IROC with 305 TPI. This winter I'll be in deep poop with 3 holes.
2 holes seems to work best for me, that's what I had in the old tstat.
2 holes seems to work best for me, that's what I had in the old tstat.
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