Kaisers´s thermostat free from worry?

[T-Cut]

Originally Posted by Bastelmann

My mechanic, an experienced and admitted Rover/MG-expert, suspects, that Kaiser´s alloy thermostat could develop contact corrosion at the juncture to the engine block followed by problems or damages when the thermostat housing has to be removed. Does anyone have thougths, experiences or comments to this issue?

Contact corrosion (galvanic corrosion) occurs when two different metals are in wet contact so that an electrolytic cell is created. The relevant word here is different. There's a classic list called the electrochemical series which lists the metallic elements in order of their electrode potentials (expressed in volts).

So, the two metals must have different electrode potentials to create a cell. Metals that are well separated in the list will generate the highest cell voltage and therefore corrosion risk. Since the engine block and the thermostat housing are both fabricated from aluminium and aluminium alloy, the probability of such corrosion is pretty small and likely negligible. However, if the engine block were iron for example, contact corrosion would certainly be an issue.



TC

[Dorset Bob]

I agree with above.

Ask any Triumph Stag owner trying to get the cylinder heads off.

[COLVERT]

Originally Posted by Dorset Bob

I agree with above.

Ask any Triumph Stag owner trying to get the cylinder heads off.

Probably as difficult as it would be to remove a Triumph Stag owner from his beloved Triumph Stag.---

[kaiser]

Originally Posted by Bastelmann

My mechanic, an experienced and admitted Rover/MG-expert, suspects, that Kaiser´s alloy thermostat could develop contact corrosion at the juncture to the engine block followed by problems or damages when the thermostat housing has to be removed. Does anyone have thougths, experiences or comments to this issue?

Firstly, there is no direct contact, as the O-ring is between the block and the parts of the kit. Secondly the materials are the same (aluminium) so there is no transfer of electrons thus no galvanic corrosion, and thirdly the antifreeze you use, contains anti corrosion agents that will largely contain corrosion in any case.

The answer to the above is clearly, tell him to worry about something else!

Then we have the usual story of perfect plastic thermostats that don't leak. That is nonsense. I have had things fail, i have shown repeatedly how and where and when things fail in this department. We of course have extraordinarily lucky people, they do exist!! https://youtu.be/6R5MqxcKdV8?t=41
for us mortals, I have had 3 or 4 thermostat housings, T-pieces and other assorted plastic bits fail. I am perfectly able to see if a thing has a crack or not, mine cracked! as in separate into more pieces, in one case the ultrasonic welding had failed! This is NOT flattened O-rings irrespective!
That might just be me, but that is what caused me to build these thermostat housings years ago. If anything, history has backed my view on that count, or we have a fairly big number of complete fools running around with expensive paper weights for thermostats!!

But who am I to talk? Let the owners do the talk thing!

Lastly, the cars DO NOT drive to cold with an 80 degree stat in them. I am getting tired of seeing this repeated ad nauseam. They run at temperatures of 85 to 95 degrees typically, with this thermostat. That is not too cold at all. It is slightly colder than the standard set-up, but it is well in the operating range of the fuel dispensing systems ability to regulate within the standard parameters. I have always felt these cars were hot and bothered in our climate at least, and I did something about it!

Everyone is of course totally entitled to own opinions, I just want to put the facts on record and not let those views stand uncontested.!

have a lovely weekend!

[COLVERT]

There is, I guess, a reason for just about anything.---

There must be a reason why my 18 year old thermostat and housing are still functioning well. No leaks and the engine temperature OK.

But why I wonder.----

One of life's little mysteries.----

[genpk]

had Kaisers metal thermostat in 3 of my rover 75 for several years and had no leaking issues with any of them, only one had a sticky thermostat which was easy to change.
I will also mention on one other rover i had, i left the nylon thermostat in and placed a support bracket for the long radiator hose near the bleed screw as i had suspected alot of the leaks originated from the weight of the hose full of water
flexing when the engine moves, slightly pulling on the thermostat housing putting pressure on the O rings and also the plastic weld joint.
I did this after reading Mgr originally were going to put supports in for the hoses but eventually decided not to.
Think i have got about 100,000km out of that nylon thermostat housing and still going with no leaks.
The metal thermostat really is what should have been done by mgr and over here in Australia is a must have with our summer heat.

[SD1too]

Originally Posted by COLVERT

There must be a reason why my 18 year old thermostat and housing are still functioning well. No leaks ...

Thank you very much Jon, you've highlighted something which I had overlooked. Your diesel doesn't leak because the 'O' ring isn't subjected to the movement which I've identified as the cause on the KV6.

Originally Posted by genpk

I will also mention on one other rover i had, i left the nylon thermostat in and placed a support bracket for the long radiator hose near the bleed screw as i had suspected alot of the leaks originated from the weight of the hose full of water, flexing when the engine moves, slightly pulling on the thermostat housing putting pressure on the O rings and also the plastic weld joint.

That's exactly the premise underlying my solution Peter.

Originally Posted by genpk

Think i have got about 100,000km out of that nylon thermostat housing and still going with no leaks.

Thank you Peter. That's very valuable evidence which demonstrates that it's movement which is responsible.

Simon

[DMGRS]

Just a quick one - we're a bit late to the party, but if anyone is on our waiting list for a Kaiser thermostat kit we offer an original plastic item at half price to 'tide you over' - £19.99 for the kit.
This is only for those with a Kaiser thermostat kit on order with us; PM me if you need to arrange this.

Just to add, we had one of the first Kaiser thermostats fitted to a past ZT190 and there were no signs of corrosion even after being fitted for several years.

Cheers!
Mat

[Bolin]

Originally Posted by genpk

I did this after reading Mgr originally were going to put supports in for the hoses but eventually decided not to.

Pardon my curiosity, but where did you read that?

Certainly agree the movement of the heavy hoses is the culprit. My curved pipe fractured due to this, causing massive coolant loss. Now sorted with Kaiser housing and 88 degree thermostat.

[p2roverman]

Originally Posted by Dorset Bob

I agree with above.

Ask any Triumph Stag owner trying to get the cylinder heads off.

As the owner of a Stag I would concur, but fortunately have not had to do this, just dropped in a good running engine instead. This car is for sale should someone want some open top summer motoring......