MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Cold thermostate ...Here we go agian !!!

This is for my truck, and in genral,

This the start of the 3rd year for this problem....

When I start my truck in the morning for the 1 st time it wants to over heat, then will run fine all day unless I let it set for 6-8 hours....this occures only during the cooler weather...I have analyized this down to the thermostates.

I dont know to fix the problem,,,,My therory is the thermostate is staying colder longer along with the truck engine metal and is not catching up to the hot antifreeze thats building up pressure...sending my gauge into the red....I have tried stat after stat...on my 4th tring to find on that works....I think something changed in the manufaturing of stats in the past 3 years...I cant figure anything else.

What I have done....

cut the core out of the stat and re-installed, By-passed the heater core, put in 10 minute flush with out antifresse (water only) then ran it 3 days then flushed it out, put in a factory dealership stat, and samething is still occuring. (All hoses were replaced last year)

Im goin to cut out the giggle pin and drill the hole to a bit bigger, not sure this will work.

Any body have a therory as to the stat and how to fix....overheating 1st thing in the morning and having to pull to the side of the road and pop the cap is along side busy traffic is getting old

BTW most of the time the stat will open on its own...but its scary to watch that needle climb into bed with the big letter "H".

thanks
prop
Prop

REVISE... What I have done

taken an old stat, cut out the core and re-installed, drained old anti F., put in water and 10 min. flush ran (with no antiF. Ran it 3 days, drained and flushed with water, installed new anti-F, and new stat, burped out all the air, have not hooked up heater core yet, and has ALL new hoses last winter.

Prop
Prop

Prop,
You are VERY sure you are not installing the stat upside down, right? I gotta ask... The sypmtoms are consistent with the temperature-sensing part of the stat not being submerged in the water in the engine. You say you got all the air out, so that shouldn't be the problem. Where is the temperature gauge connected to the engine? You didn't buy the stat at autozone, did you? What brand of stat are you using? What temp?
David "no answers, just questions" Lieb
David Lieb

Some of the thermostats have a tab that fits down into the head or block. Maybe you are not running the correct thermostat for the application?

Also sounds like air in the system. I remember even the midget heating way up like that just after changing antifreeze and being unstable until all of the air got burped into the expansion tank.

What kind of truck, U.S. or Japanese?
glenn

You mean there is an upside and a downside on the stats....LOL...

Sorry I couldnt resist

yes it is in properly, and I got all the air bruped out, Im was using a high grade "STANT" from an indepenfent parts shop...but it doese have the wax stiint....Im currently using a toyota factory stat 88C temp. and it also has the wax stint and yes it over heated on me yesterday morning same as the stant stat

I went ahead and removed the giggle valve in the stat face, and redrilled the hole to a little larger then an 1/8th inch seems to have cured the problem this morning...but it was fairly warm outside this morning as well, so Ill have to wait till tomarrow morning when its colder to see what happens....good news is it took longer to warm up

Still I wish I knew why the stats are not working vary well... I just dont want to be messing with this all winter...Id love to get thur one winter trouble free on the truck

prop
Prop

Its a 93 toyota 4 banger 22re engine

no tabs but you are supposed to position the giggle valve toward the firewall according to hayes....I have a gut feeling the wax is differant from years past, or they are making them differant.

prop
Prop

Great news!!


It worked, pulling the giggle pin out of the stat and drilling it a bit more then an 1/8th inch worked like a charm, it went where it was supposed to and stoped..and never got close to over-heating....

It did take about twice as long to warm up, but as long as it dosnt overheat anymore I can live with that.

someone really needs to take those 8 year old little china girls that are making those stats out back and give them a good hinnee spanking for doing a poor job assembling those stats, after all if they are going to only get paid 85 cents per WEEK, they should put there heart and soul into it. (yeaah im being arrogent and absurd)

prop
Prop

Prop
I know I'm on the other side of the world but there seems to have been a change in thermostats here as well. What I have found is that the old ones had a jiggle pin and also a small nick in the side of the door whereas the new ones don't seem to have the nick in the door. The result is that when you start your engine the water flow shuts the jiggle pin and because there is no flow at all to the thermostat (sometimes) there can be a overheating problem further back in the engine before the thermostat gets the signal. Removing the jiggle pin leaves too big a hole and as you have found out warmup time is longer. I have found the best answer is to leave the jiggle pin alone but drill a one to one and a half mil. (1/16"max.)hole either in the door or near the jiggle pin. I don't know what your truck is but if the thermostat just sits on the flat it doesn't really matter where the hole goes but if it's up on it's edge the hole needs to be at the top as that will allow any air bubbles that could arive there to escape.
WilliamRevit

Prop,
i could have sworn you had a bad condensor.

Don
don g

Hey william

Thanks for the thought, it seems to be working really well at the moment...It dosnt bother me that it takes longer to heat up, Im just glad its not over heating....This is strange thought, But I think they are putting the giggle pin in upside down....cause the FAT part of the pin is under the stat, so when there is pressure the stat is completely closed...(and yes I have the stat installed correctly...anyway, its running great "Agian" with out the giggle pin.


Hey Don G.

I just replaced the stat condenser...LOL, could it be the stat points...LOL

prop
Prop

This thread was discussed between 05/10/2008 and 08/10/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.