Finally got the timing problem sorted and no serious damage done. I've decided to fit a new stat.before re-fitting all the engine bits and bobs. Have just been reading comments in AA. What is the latest concensus of opinion as to which stat is best? and whether to drill series of holes as a by-pass?
PS Stat fell out before I could note which way round, heavy spring inwards or outwards?

- (#13859) gordon davies, 21 Oct 04 13:47

Gordon. The Toyota stat is part No 90916 03046 and the "O" ring type seal is part No 16325 63011. This stat has an opening aperture of 30mm as against the after market stats which are usually, but not exclusively, 25 mm opening. This 5mm increase in opening diameter does give a much bigger cross sectional area and, in my opinion, is important for adequate coolant flow.
The spring/capsule sensor goes inwards towards the engine, sensing the block coolant temperature and not the temperature of the returned water from the radiator. Unusually, these stats are on the return side of the coolant system. I have two stats, one for summer and one for winter. The summer stat has three, 3 mm bypass holes, drilled in the stat flange. The winter stat has one, 3mm hole. I modified these stats following a lot of discussion and experiments (by other contributors)and, after four years of operation, coupled with an improved temperature gauge, I have never had any cooling problems and my "winter stat", with one bypass hole, allows adequate warm up for the heater during the cold months. I think that the standard, undrilled stat, in summer, does not allow adequate cooled water to get back around the block & head, before that critical "head cooking" situation is reached, especially after a high speed or hilly run, followed by a slow road speed. There is not a lot of "ram" cooling air over the radiator but, what there is, does, I think, play an important part.
Have a look in Ace Answers and you will see lots of information on stats and their modification (or otherwise)

- (#13859) John Davis (Leics), 21 Oct 04 16:39

John
From your comments and those on AA, I now believe that the stat may have been a contributing factor in my "boil-up* and the consequential results. don't really want that again, so will again heed your advices and fit a Toyota stat with the 3x 3mm holes. Presumably these are simply drilled into the flange just inside the 'o'ring seal. Perhaps I'll start with 2 x 3mm holes as winter is approaching - I'm not too concerned with fast warm-ups. Anyway, they tell us that global warming has put an end to bitterly cold winters !!! Do you recommend any lubricant on the seal ?

- (#13859) gordon davies, 21 Oct 04 17:25

Gordon. Yes, holes drilled, in the flange, just inside the seal. There is, already, the standard "jiggle" valve in the flange, acting as a bypass but these can get blocked and it is prudent to have this jiggle valve at the top of the stat housing where there should be less of a chance of debris build up. If you find that you have drilled too many holes and that "warm up" is too slow, it is easy to plug one or two of the holes with a brass nut & bolt, rivetted for security.
Being a bit parsimonious, I don't buy a new seal when I do my annual stat change so, yes, I put some jointing onto the flange. However, a new, and softer seal ring beds down very well into it's recess and should not need any jointing or lube.
Don't you believe it about bitterly cold winters being a thing of the past. My holly tree is loaded with berries, an infallible indication of harsh times to come (So my old Gran used to say :-)
- (#13859) John Davis (Leics), 21 Oct 04 17:45