Car overheating - TA22

[roadkill]

Hi All,

i've now had my TA22 on the road for 3 weeks and have come across a bit of an odd overheating prob. Basically when i start it up the temperature rises well above normal operating temp - today it was over 100deg according to the guage, then miraculously it just decides to drop down to just below 80 and continues to drive perfectly for hours. I replaced the thermostat the other day (it's actually getting higher since i did this) thinking that the old one was funked. Today when it was at 100deg (by the guage) i could take the rad cap off and there was no boiling over or anything - mind you there was no water flowing through. I'm a bit stuck as to what it could be that's doing this. So far i can think that it might be the following

Thermostat (might have been a dud)
Radiator blocked (going to flush it out tonight)
Water pump???
Temp sender from thermo housing playing up.

I'm really stuck on this and trying to find out suggestions or if people have had a similar problem in their cars. I think it's just really odd that it is only on initial startup that it'll get hot, then it's fine. I must add it doesn't get to anywhere near freezing where i live so that (should) eliminate that possible prob too.

Thanks

bEn

[legend]

get it up to 100 deg and check with another gauge or thermometer
could be waterpump,radiator, as u mentioned
also flush the heater core on a low pressure

[stidnam]

Sounds familiar.

My 22 did this also. Starting from a cold overnight state the temp gauge would rise at a normal rate but would not stop where it usually did when warmed up but would creep off the dial. Check of the radiator and cap showed full fluid & it wasn't boiling. Now if I just ignored this after a few minutes it would miraculously just fix itself and start to fall back to where it usually sits once fully warmed up. Took a lot of will power to continue driving like this when there was high potential to stuff the motor but I had no choice the first time and decided to push my luck the next few times and see if it fixed itself again.

I thought that it was either a dodgy wiring connection somewhere or the thermostat was stuffed. I replaced the thermostat with a new one and it never did it to me again. Having said that this has only happened to me about 5 times in the 3 years that I have been driving the 22 and I only had the last 6 months driving on the new thermostat so it may not have fixed the problem at all.

[Aphox]

I also had something similar to this occur. It still occurred after a cleaned/reco'd radiator, new hoses and new thermostat. Fluid was still moving around and not exceptionally hot. Perhaps an age related wiring/sensor issue by the sounds of it, if its coming up as a common thing?

[Grega]

aside from rotting welchplugs in my block, my radiator was blocked up in my 22
nothing a good reco 3 core didn't fix.
no more overheating after that puppy went in

[Akaoni (Casey)]

Hey Roadkill

My TA22 3TG Hybrid has been doing exactly the same thing for years but intermittantly (usually in winter - go figure???).

Scared the s*** out of me the first couple of times but I'm used to it now.
I really should fix it so I know if the engine ever does really overheat, tho.

I know the engine isn't actually overheating 'cos the thermostat isn't open and the engine feels cooler to the touch than when the gauge shows the engine at normal operating temp. Also, there is no way that my engine heats up that quickly.

I've tried replacing the thermostat and I think even the gauge.
No luck.

I was thinking that it's either a common old age 'glitch' in the gauges or something wrong with the sender or wiring.

I'm keen to help figure this one out.

Cheers.

[sleeektoy]

I had this problem with a 2T-B in my TA22 but not in my 2T-G when i switched it over.

I never really got to the bottom of why it did it either, but i have my suspicions...

- on a 2T/2T-G the temp sender/sensor is just under the thermostat.
- this positioning is the highest point in the upper part of the water system
- heat rises, therefore the temp will be at its highest just before the thermostat.
- because the thermostat is closed, the water is rather static at that point
> therefore, it may be reading high until the point that the thermostat opens (78-80 deg), and if you've tested a thermostat before, they take a while to open unless completely surrounded in water at(or greater than) the opening temperature.
> gauges on a TA22 (in my experience) take a while to register changes too (drive out of a petrol station and see the gauge rise 1/4 tank more after 1-2km)

All the delays, and the positioning of the sender/sensor IMHO attribute to the high initial temp on the gauge and then it all equalises once the thermostat is fully open.

It's my theory anyway

EDIT: something i changed between the 2T-B, and 2T-G was from a vent to air, to a recirc water bottle system, from the radiator overflow. Just had a thought that if an air bubble was to get around the sensor (under the thermostat) it would give some really weird readings, esp if there is steam in the bubble when warming up!

[roadkill]

Hi,

from the other people i've talked to about this i've found out that apparently it can be somewhat common. As to why there is no definate answer but.... I've been recommended to drill a small hole or two in the thermostat (bout 4mm) as this will help to vent the thermostat if any steam gets in there or other gas in the system. This could be what makes the thermostat show a higher temp as this will heat up easier and quicker than water. The heat transfers slower from the gas to the thermostat (especially when there is cold water above it) and hence takes longer to open and showing a higher temp. I've been told by a few mechanics that do this that the problem no longer arises. The hole is small enough to transfer any gas but small amounts of water therefor letting the thermostat do it's job.

I've just gotta pull my finger out and drill the holes and see how it goes, i'll post on here the results.

Thanks again,

bEn

[w810sc]

most thermostats should already have a hole to help bleed any air out of the system.

fonz