Themostat Bolts

[Midge]

Hi Folks, I have a '89 1.9 DG with a plastic thermostat top held in by 4 bolts.

I say bolts, but I can't see a straight edge anywhere on any of the bolt heads - they just look like rusty dome heads with no way to turn them.

Dunno what's for the best - hacksaw a slot and try to get a screwdriver in, chisel off & drill out, hammer a socket on...

Looks like the top is an available replacement part but obviously I'd prefer to just need 4 stainless bolts and have done with it, so if I can avoid trashing the top I'd be happiest.

Cheers for any advice!

E D I T TO ADD - another related question.

If the thermostat was missing/stuck-open, would the temp gauge needle still come up a little, or would it be pinned to the left as per a broken sender fault

[Bigjcc55]

If you are changing it just for the gauge fault I would check the wiring to the sender it's the hardest of the two to reach, the terminals inside the plug are bad for corrosion.
And you're needle prob would eventually come up a bit.
Check the wiring first.
And if the housing has to come off I normally smash them (carefully) to get better access to the bolts, brickwerks do a fitting kit with bolts clips and seals for the senders.

[CovKid]

Theres your answer. Sets range from £15 to £25 or more but they save HOURS of work.

https://club8090.co.uk/forum/viewtopic.php?f=37&t=130931" onclick="window.open(this.href);return false;

[Midge]

If you are changing it just for the gauge fault I would check the wiring to the sender it's the hardest of the two to reach, the terminals inside the plug are bad for corrosion.
And you're needle prob would eventually come up a bit.
Check the wiring first.
And if the housing has to come off I normally smash them (carefully) to get better access to the bolts, brickwerks do a fitting kit with bolts clips and seals for the senders.

Cheers matey. I waned to put a new thermostat in for peace of mind as I don't even know if there's one in there currently. The sender swap-out was all ready to go and I planned to do the thermostat first to hopefully reduce the gush of coolant when the old unit came out.

Anyway, like you say, the only way it looks to be coming off is with a dremmel or similar mini-cutter to take out the bolt heads and I'll treat the whole top cover as disposable when I get to that stage.

Am hoping to do it in-situ but if absolutely required then I guess the whole housing might need separating from the engine casting. The 2 allen bolts holding it in there are rusted to the max so that will be another fight, on another day...

So I just did the sender swap anyway, got about a pint of Peckham Springs down me sleeve in between the swaps and can happily report that I now have a functional water temp needle, yipidee skipidee

My gut feel is that the thermostat is either stuck open (unlikely?) or not even fitted, as it takes a long time for the needle to come up and the coolant really did gush forth from behind the sender.

I'm not going to let a missing thermostat stop us heading out on a few trips, now that I have a gauge to keep an eye on, result!

[Midge]

Theres your answer. Sets range from £15 to £25 or more but they save HOURS of work.

https://club8090.co.uk/forum/viewtopic.php?f=37&t=130931" onclick="window.open(this.href);return false;

Cheers CovKid, this might be needed for the allen bolts holding the thermostat housing to the engine casting I guess?

There isn't enough meat on the dome/hex top-cover bolt heads to catch them with the tool tip, for sure...

[CovKid]

Yep, normally these bolt grippers occupy the same kind of space a 19mm socket occupies so room can be an issue. However, if you let the tool sit a little outside the socket, you can get in a tighter space. I was stunned that they tackled an allen bolt though. They can be real pigs.

[AdrianC]

Yep, normally these bolt grippers occupy the same kind of space a 19mm socket occupies so room can be an issue. However, if you let the tool sit a little outside the socket, you can get in a tighter space.

Plus, the hex on the outside allows you to use an open-end spanner to turn them.

I was stunned that they tackled an allen bolt though. They can be real pigs.

Second time I used mine in anger (first time was the 'stat housing, too!), t'was on the allen bolts holding the (snapped off) plastic coolant stub to the RH head. The ball end of the allen key had snapped off in the bolt head... The Irwins did the job without breaking a sweat. WONDERFUL things.