4.2 V8 - Coolant Hose Change/Thermostat/Water Temp Sender

[The Dogster]

Dear Fellow Cerbera lovers

I embarked last weekend on replacement of coolant hoses/pipes for my 97 Cerbera
I had already purchased full AJP hose kit inc behind engine link hoses in Silicon and the Stainless steel coolant manifold set from ACT
I also took the opportunity to replace the Thermostat/Water Temperature sensor and radiator cap - these were sourced from TVR Parts - temperature sender being the Bosch Motorsport upgrade

The dismantle and removal of the old pipes was relatively straightforward - I decided to cut the more difficult hoses with a Stanley knife and then proceed to destroy my knuckles getting the old Jubilee clips off. I took the chance to remove the bottom engine cover to access the bottom pipe - clean everything and prepare for the refitting. Having took photos of the old pipe work/locations it was still difficult to fit some of the pipes - however after around 3x hours all were in place.

This next chapter is a common one - refitting the capillary pipe for the Temp Gauge resulted in ...yes you guessed it.....broken capillary - not a problem as I will get Dom to fit me a new SPA gauge later. After doing up the old capillary and fitting new temp sensor I had taken from the start the following steps taken from the Cerbera workshop manual:

1) Remove Rad cap
2) Disconnect lower cooling pipe
3) Drain system
4) Replace pipes/hoses/thermostat/re-install sender/sensor
5) Top up coolant via reservoir with 3 parts water/1 part antifreeze - this was done carefully and slowly with the radiator bleed plug removed - when fluid spilt from Rad bleed plug I refitted plug
6) Bled air from bleed valves on both coolant rails - re-tightened
7) Checked Header reservoir and topped up
8) Ran car

At this point I was feeling quite confident - the car warmed up and thankfully the fan on reservoir side of the car came on shortly followed by the other fan. Now because of my broken capillary pipe I have no temperature gauge - as the car idled it started to vent from the header.
I turned car off and opened driver side bleed valve - sure enough it vented air - retightened when finished or spurts of water started to appear
Repeated on passenger side
Let cool a little and took cap off header - topped up a little
This process went back and forth 5x or 6x times - however I am thinking air block - when feeling ALL pipes they are hot 0 except the bottom rad hose - this is warm - does this mean some kind of air block?

Went inside and consulted this wonderful forum (which I see is considered to be “right leaning” - another subject for another day perhaps) - I checked the obvious which was had I put pipes in right place - only place this could be was passenger side pipe from coolant rail down to ACT stainless hose - all are correct

Went back outside - checked coolant level - re-tightened hose clips - checked for any leaks - all ok

Started car which by now was a little cooler obviously - car ran - warmed up - fans cut in - steam again started to vent again from header - except it took longer this time - again bled coolant pipes - this time I think that this was venting steam

Too cut to it - I think the engine is boiling the water because it is not circulating properly - so checking bottom rad pipe again it was not hot but warm - loosened Bleed Plug at top of rad and slowly undid - water started to seep and it was Luke warm - then it surged a little and I replaced the plug - when feeling the side of the rad it now seemed much warmer even hot - again re-topped up coolant/fluid and re-started car - same things happened - at this point I thought I would seek some much needed advise on this forum

I am not a mechanic by any means but not completely useless - I would appreciate a step by step guide as to what to do next to diagnose and fix - with that I post some pictures and video to aid any advise that will be much appreciated - Nigel

[The Dogster]

Just re-read my air bleeding schedule - clearly it says that you should bleed cooling rail valves BEFORE starting the engine - I topped up fluid and then started engine BEFORE bleeding cooling rails - logically this says to me that I HAVE DRIVEN THE AIR around the system BEFORE bleeding..........does anyone agree that this has caused air to be in the system at another point and now unless I re-drain it will continue to boil?

[The Nige]

Not completely sure but is the thermostat fitted in the right direction. Sound very similar to an experience I had after replacing the thermostat.



Cheers

Nigel

[The Dogster]

Thought I’d got this right Nigel? See old one
Pic shows pipe that goes horizontally - parallel with Radiator
Still if someone could confirm

[The Dogster]

Photo from TVR PArts - pipe up to rad sits on top - small right angle pipe sits on left hand side - closest opening has long horizontal pipe which runs parallel with rad

[The Dogster]

Bugger me see below from another thread - I have Gates type thermostat and looking at below it’s wrongly fitted - the way TVR parts picture looks is that it is correct way around in fact it’s not the flange should sit on top and the down pipe from rad attaches to that flange side........thanks Nigel you were right😎

[The Dogster]

[MoonMonkey]

Hi Dogstar

That’s correct your original thermostat is the Wahler type, your new one is a Gates. The bypass is plumbed differently.

I learnt the same lesson a few years ago

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

[The Dogster]

Hi Moonmonkey - thanks to your thread I can see now - never assume and never go by a picture - lesson learnt
Thank you both (Nigel too)
Nigel

[The Dogster]

Evoila - Please someone shout if it is wrong - Just waiting for my amazon Prime anti freeze...

[ukkid35]

Like MoonMonkey I have spent some time looking at the thermostat options

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

I reckon the Wahler is better quality and probably flows better than the Gates type

You could try contacting Russ, aka Sonnylad, as I think he may have some available

Meanwhile it is probably worth hooking up your Android to the ECU so you have a temperature gauge

[notaping]

Quick test - the bottom 2 ports are the direction of flow when the water is cold. The top port opens when the water is hot. So hold the unit under a tap and see which ports allow cold water through. They should be at the bottom. The third port points up. You can also pour a kettle of boiling water through it to check that the thermostat opens.

[The Dogster]

Hi all thanks for messages - all working normally - tested thermostat before fitting and bled as manual suggests - all good

Now to sort the gauge - will take to Dom I think

[ukkid35]

The Dogster said:

Now to sort the gauge - will take to Dom I think

The usual procedure is to remove the gauge and send it to the ironically named Speedycables

You only need to send the gauge, as it will be returned with a brand new capilary line

Then you can think about the routing of the capilary, I have changed mine so that it follows the chassis rail, rather than being strapped to the coolant rail

[Mags]

The Dogster said:

Hi all thanks for messages - all working normally - tested thermostat before fitting and bled as manual suggests - all good

Now to sort the gauge - will take to Dom I think

I got mine done here: https://www.pistonheads.com/gassing/topic.asp?h=0&...

[The Dogster]

Thanks Mags very useful - have contacted Alan.