Thermostat Removal / Replacement - Guide + Pictures

[debaron]

Hi all,

Was looking into doing mine a while back and couldn't find a good guide on here for beginners so did one myself.

Also documented for 'The Resource' too.





Thermostat Replacement - step by step

TVR Serpentine 400


First things first!



Park car facing uphill

You will need:

Pen
Paper
Hylomar Blue/Locktite non drying gasket- unless ordering a thermostat housing gasket
Superglue
socket set with long reach extension
10 - 15 mm spanners
Thermostat - obviously... (I got mine from Racetech TVR in Henley)
6ft 3x2" wood or similar for extended bonnet opening - optional


NOTE - If your water temp gauge sender is playing up - during this task is an ideal time to replace it!


1 - Prop open the bonnet with wood or use standard sore-back TVR bonnet prop





2 - Remove cable ties and unplug the wires from coil/ignition amp/distributor input/coolant temp sensor (not plug leads...yet!) - taking notes of where they go








3 - Remove Jubilee clips holding swirl pot to thermostat housing tubing. Remove rubber tubing and king lead. Make a diagram of the distributor / plug lead arrangement


NOTE - ALTHOUGH THE HOUSING CAN BE REMOVED WITHOUT REMOVING THE DISTRIBUTOR YOU WILL FIND IT A LOT EASIER TO REFIT WITH THE DIZZY OUT OF THE WAY.

I DIDN'T TAKE MINE OUT UNTIL REFITTING SO MY PHOTOS DO NOT FOLLOW THE DESCRIPTION









4 - Remove plug leads and dizzy cap. MAKE A NOTE/PICTURE OF EXACTLY WHERE THE ROTOR ARM IS POINTING. BE OVER ACCURATE!!! Mark distributor position with a scratch/mark that is contiguous with the manifold and dizzy housing.





5 - For PAS equipped cars, remove the PAS hose clip completely and push hose out of the way.

6 - Slacken off dizzy clamp and remove using 15mm spanner

7 - Firmly pull dizzy out of it's hole. Ensure you plug the dizzy hole with a clean rag or something that won't shed a load of stuff or fall into your engine





8 - slacken and remove top thermostat bolt






9 - Slacken and remove bottom (slightly obscured) thermostat bolt. I used a cheap T-Bar thing from Wilkinsons but you should definitely use real tools if you have access to them.







10 - Crack housing away gently to reveal old thermostat. Some water will probably leak out at this point









11 - Old thermostat out





12 - New Thermostat - note constant flow hole at 12'o'clock position





12 - Clean the thermostat housing face with tissue/fingernail/non sharp tool. Apply a small amount of superglue to the face at top of the thermostat housing hole.
Firmly seat new stat with constant flow hole at 12'o'clock. Hold in place for a few minutes while whistling a favorite tune (optional)








13 - When you are satisfied the thermostat is firmly stuck in, coat the mating faces of the housing and manifold with liquid gasket or fit the gasket supplied with the stat and reassemble. Care should be taken not to disturb the thermostat.







14 - Refit the distributor. MAKE SURE THAT UPON THE DIZZY SETTLING IN THAT THE ROTOR ARM IS EXACTLY WHERE YOUR PICTURE/DIAGRAM SHOWS IT. If not then remove dizzy again and resettle correctly. Align the timing mark on the dizzy to the mark on the manifold. Refit plug leads and all electrical connections.



15 - With all connections replugged, fit the swirl rubber hose to the thermostat housing pointing up as shown. Tighten it's jubilee clip moderately. Fetch a kettle/jug with spout and pour water into the tubing slowly until water holds it's level at the top of the tubing.

16 - Reconnect the tubing to the swirl pot.

BLEED THE COOLING SYSTEM PROPERLY - follow the excellent instructions here:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by debaron on Friday 16th April 00:26

Edited by debaron on Friday 16th April 00:29

Edited by debaron on Friday 16th April 00:32

[lotusandy]

Well done for such an comprehensive guide, pics 14-15 are a useful ref for the 3 coolant temp sensors also!

Thanks Andy

[brazenskies]

It's a real shame the photos aren't available anymore.

Out of 10, with 0 being "piss easy", and 10 being "fk doing that again" how would you rate this task?

[wuckfitracing]

0

[TV8]

wuckfitracing said:

0

I have changed the thermostat on a pre serp and that is easyish. Taking out the distributer and replacing in 100% the same place would never appear on my piss easy list!

[debaron]

Holy thread revival batman!

I wrote the this original guide and afraid the photos have been deleted from my web server.

However - the my slightly edited guide that Derek from RV8 resource kindly reproduced is here


http://www.rv8r.co.uk/thermostreplace.html

[debaron]

TV8 said:

I have changed the thermostat on a pre serp and that is easyish. Taking out the distributer and replacing in 100% the same place would never appear on my piss easy list!

cuz of the way the cogs on the cam and dizzy drive mesh, as long as you have made good marks (on the rotor arm and other reference point AND on the engine and dizzy housing), getting it back in the right place is actually very straight forward. Arm gets lined up first then you slide the housing round til your other marks line up.

[TVR Beaver]

Did mine last night... I tend to take the alternator off to one side (just 2 bolts) instead of removing the dizzy

Siphon the coolant out from the swirl pot into a bowl and you just at the right level.. didn't spill a drop

all done in about 30 mins

my old stat had become lazy and was not opening as much as it should .. resulting in it taking longer to cool down once hot... all sorted now

[Chuffmeister]

It's easy. Before you remove it, mark both the dizzy and the hole where the dizzy enters the block. I used a small driver and scratched a line in them both. Easy and clear to line up and it won't rub off. Find no.1 HT lead and mark it on the dizzy cap (perm marker will do it). Remove the dizzy cap and take a couple shots on your phone of the orientation of the rotor arm. Now remove the dizzy.

As for the thermostat housing, I found it easier to unbolt the lower bolt of the alternator and push it out of the way.

The rest is simple. Reassemble in reverse order.

[TVR Beaver]

I know.. but taking the alternator out IMO is even easier... you don't have to touch the dizzy, cap, rotor arm, leads or anything... Two bolts, alternator moved to one side.. and your in... 30 seconds.. and nothing to go wrong

[Bluebottle]

I guess i must have small hands or something, as i am able to replace mine without removing the dizzie or alterntor? I just take the dizzie cap off to one side and disconnect the top hose to the swirl pot.

[TVR Beaver]

I think I did mine like that before, but with the power stearing pipe its a bit of a fight... and I could not be sure the stat had remained seated so ended up removing the cover again to check LOL.
However you do it, its a straight forward job

[Bluebottle]

TVR Beaver said:

I think I did mine like that before, but with the power stearing pipe its a bit of a fight... and I could not be sure the stat had remained seated so ended up removing the cover again to check LOL.
However you do it, its a straight forward job

yeah i know what you mean lol. i use a little blue hylomar on the stat rim to hold it in place and use a gasket for the stat cover, I think if i was using gasket sealant and not a gasket for the cover i would probably remove the dizzie.

[brazenskies]

debaron said:

Holy thread revival batman!

I wrote the this original guide and afraid the photos have been deleted from my web server.

However - the my slightly edited guide that Derek from RV8 resource kindly reproduced is here


http://www.rv8r.co.uk/thermostreplace.html

Good threads never die

Thanks for the link. I've had it out and checked and it wasn't too bad at all

[davettf2]

Peeps, I'm in the small hands brigade, no need to remove dizzy or alternator to change either thermostat or sensor. Just remove cap, rotor arm and the leads from the lefthand bank.

Also in the nut brigade for the dash top, nuts are easy with a spinner ratchet, but I have shortened the offside stud by 3 mm to make removal easier.

regards
dave

[quattrophenia]

Never done this job before so a bit hesitant. I'm a bit more confident if I don't have to remove the dizzy though.
What thermostat are people using, the one that opens at 74oC or 82oC???

[Chuffmeister]

82 degs large bore thermostat. Mixed views about removing the dizzy on here from what I remember. Eitherway, its an easy job, just mark the dizzy and the block at the base of the dizzy, so it can be put back in the same place. Take a snap if the position of the rotar arm on your phone so you can reposition the rotar when you put it back in. Then simply unbolt the dizzy clamp and pull the dizzy out. I did remove the dizzy as it made access much easier. In fact, it has been out and put back in a few times using this method, without any issues.

[carsy]

82 is what you want.

[barnpot]

I am going to attempt this soon. Can someone post the instructions with pics again? I get a 404 when i try access http://www.rv8r.co.uk/

thanks,

david

[quattrophenia]

In the end I disconnected the battery, slipped the belt off, unplugged the alternator electrical connector from the back and removed the 2 securing bolts to roll the alternator out of the way. This allowed enough access to the thermostat housing bolts. I did however have the bonnet off at the time as I had re-cored the rad (hence wanting to do the thermostat at the same time). Being able to tackle the job from the front did make it a bit easier than from over the N/S wing.