The higher priced Altrom products are usually OE.
Thermostat; to drill or not to drill a bleed hole?
- Thread starter Drew99GT
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I always drill a hole or 3.
Never had an issue.
Never had an issue.
All the jiggle does is make filling it easier. Once its filled the jiggle does not do anything.
If you drill a small hole keep it very small. Air flows very well through any small hole and you do not have a lot of air to get rid of.
I've done a couple holes in a couple different cars with the desired results.
These were typically replaced thanks to being "sticky". I don't see a stat slamming open and closed over and over being all that good for the engine... thermal stresses and what not.
It took about 3x 1/8" holes to overcool a 96 cavalier. I learned from that and typically now drill one 1/16" or 3/32" hole.
There are some shady cars I work on that trap air, and the bleeders are either rust welded in place or look like they would be. So I put the tiny hole in the stat, point the front of the car uphill, and fill as much as I can. I squeeze the upper rad hose to try to work the air out. Sometimes I'll disconnect said hose at the radiator nipple and "backfill" the engine through the hose and stat-with-hole, lifting the end of the hose as high as it will go to make more pressure.
These were typically replaced thanks to being "sticky". I don't see a stat slamming open and closed over and over being all that good for the engine... thermal stresses and what not.
It took about 3x 1/8" holes to overcool a 96 cavalier. I learned from that and typically now drill one 1/16" or 3/32" hole.
There are some shady cars I work on that trap air, and the bleeders are either rust welded in place or look like they would be. So I put the tiny hole in the stat, point the front of the car uphill, and fill as much as I can. I squeeze the upper rad hose to try to work the air out. Sometimes I'll disconnect said hose at the radiator nipple and "backfill" the engine through the hose and stat-with-hole, lifting the end of the hose as high as it will go to make more pressure.
Last year I drilled a hole on my thermostat. It caused the engine to stay cold for longer when warming up, and did nothing to keep temps down when it was up to operating temp. I found that If you want cooler temps, change out to a lower temp thermostat.
I have always drilled a 1/16 in hole in every replacement thermostat which didn't have one. I never had an air pocket problem or an engine warm up problem. I am in Northern Ohio, so it gets cold here. I wouldn't go any bigger than 1/16 inch.
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Originally Posted By: Linctex
1/16" (.062") hole at 12 o'clock
ALWAYS and EVERY time!
Why so big?......Because that is about the smallest bit that fits in a standard 3/8"-1/2" chuck housewife drill? A .020" hole would do.
I use OE thermostats & haven't ever modified them. Just make sure to bleed/burp the cooling system.
1/16" (.062") hole at 12 o'clock
ALWAYS and EVERY time!
Why so big?......Because that is about the smallest bit that fits in a standard 3/8"-1/2" chuck housewife drill? A .020" hole would do.
I use OE thermostats & haven't ever modified them. Just make sure to bleed/burp the cooling system.
OK, that didn't work! I either got a bad thermostat, or the hole flows more than I thought. It's tiny, like 3/16, and the car will hardly get to operating temp now. Gonna get a new one...
It was a nice experiment. I might throw the drilled one in boiling water to see how it acts.
It was a nice experiment. I might throw the drilled one in boiling water to see how it acts.
Originally Posted By: Drew99GT
OK, that didn't work! I either got a bad thermostat, or the hole flows more than I thought. It's tiny, like 3/16, and the car will hardly get to operating temp now. Gonna get a new one...
It was a nice experiment. I might throw the drilled one in boiling water to see how it acts.
Hole is too big. Don't go larger than 1/16 inch.
OK, that didn't work! I either got a bad thermostat, or the hole flows more than I thought. It's tiny, like 3/16, and the car will hardly get to operating temp now. Gonna get a new one...
It was a nice experiment. I might throw the drilled one in boiling water to see how it acts.
Hole is too big. Don't go larger than 1/16 inch.
I'm thinking maybe stick a bolt and nut in the hole, or maybe a tiny screw bent so it stays in the hole; any rust concerns, or will the antifreeze mitigate that?
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