CSR Heat problems solved by Zirotech headers, but...... Radiator problems?

[NeilCSR]

Has this created pressure problems in the cooling system which has 'burst' the radiator?

After the first longer run post-Zircotech, noted flecks of pink coolant spread across the RHS of the engine bay.  Header tank volume down slightly.  Initially thought (top) hose or jubilee clip problem, but once nosecone off there was no seepage at either end of the top hose, but more coolant flecks on the fan housings (plenty) and plastic deflector behind.

On the radiator there were pink dribbles from three places on the front of the core, and a couple of different places on the rear - visible once the fan housing was removed.

Not big bursts, rather very small seepages, but enough to shed coolant that the fans blew back through the top hose hole (in the deflector) into the engine bay.

Have since replaced the radiator with Paul M's spare (thanks Paul), and taken the original to a radiator specialist who can't find any problems/leaks under pressure test even at 25psi.

Replacement rad seems OK so far although minor seepage from top hose union on a long run last weekend.

Temp gauge always 100 or less, Oil temp always OK, fan cuts in properly, thermostat seems to be operating correctly.

It would appear that there is greater pressure in the cooling system than before - the only change being the Zircotech coating to the headers which could add to heat within the engine, which should show up as an over-read on the temp gauge?

Can't understand how a radiator can start to seep like this from several places (independently), unless a greater pressure has found weak points, and how this doesn't register on the temp gauge?  Only possible link is the Zircotech treatment, which has made a positive difference to the heat build-up in the cockpit.

One solution may be the use of waterless coolant - don't want to open that debate - appears more toxic than Brexit/Remain - (!!) but the obvious benefit would be lower system pressure against the downside of lower specific heat/heat removal.

Any thoughts?  Maybe I'm looking at this from completely the wrong direction?

Neil

[sjmmarsh]

I can't see how the zircotec coating is relevant. It should move the heat dissipation down to the exhaust and cat. 

It does sound like your coolant is getting very hot somewhere. The temp reading is from the sensor on the water rail in front of the pedal box, so if the flow is restricted somewhere it could be that the problem is not seen by the sensor. You may have noticed sudden drops in the temperature when you floor it on the road - this is caused by the thermostat opening on the radiator to increase the cooling and dumping the already cooled water from the rad into the engine.

Is there any seepage from the header tank cap? If you have high pressure caused by boiling it should show as seepage there as the cap has a relief valve in it. 

Just my initial thoughts.

Steve

 

[Jonathan Kay]

... and taken the original to a radiator specialist who can't find any problems/leaks under pressure test even at 25psi.

How can you pressure test the radiator while it's hot? Can the specialist do that? Could you face putting it back in?

And how old was that radiator?

I can't see how the zircotec coating is relevant. It should move the heat dissipation down to the exhaust and cat.

I thought that insulation of the first part of the exhaust system inevitably meant that the metalwork inside was hotter than before. That might make the block in that area hotter. No idea if this happens or matters in practice.

One solution may be the use of waterless coolant... but the obvious benefit would be lower system pressure against the downside of lower specific heat/heat removal.

I've never seen any comparative measurements of pressure in the liquid. The lower pressure in the headspace should reduce it, but the increased viscosity might make it lower or higher at different points in the circuit, depending on the pump, the flow, the drag etc.

That lower thermal capacity of the coolant means that at steady state and the same heat production and the same temperature on leaving the radiator the temperature on entering the radiator must be higher and/or the flow through the radiator must be greater.

Jonathan

[Rogercsr7]

Apart from the benefits of lower cabin temperatures I didn't notice any changes in my CSR200 after the Zirotec treatment. I did have an overheating problem when the temp sensor located at the rear of the engine between cylinder head and dry sump tower caused odd behaviour of the cooling fans, either off, on  all the time or working properly, due to corroded contacts. Otherwise the car always tends to run cool. When the fans stopped working I rapidly overheated and lost coolant (from the expansion bottle) when stationary after a run.

[StEVEN]

HI Neil,

If you've got coolant spray down the RHS have you checked the top rail is secure into the alloy housing, its a bit like an angled socket, my CSR200 rail popped out of its socket spraying coolant every where...the bracket holding the rail wasn't sufficient so they installed a clamp used on the 620r, all fine now!!...

Just a thought

Zircotech is interesting i was going to wrap my headers!!..did you try wrapping first?

Best

StEVEN

 

 

[NeilCSR]

Thanks for the comments.  It's definitely overheating as there has been a dribble down the header as the pressure must have exceeded the limit for the cap.

Also definitely the original rad which was seeping - pink dribbles on outside and inside of core in several different places

The Zircotec coating has made an enormous difference and it's noticed first in the cockpit where, even on a hot day, the rails can still he held by hand.  Very warm, yes, but nowhere near as burning hot as before. 

I didn't wrap the headers, done this before on bikes and it can be effective but it's never too long-lasting.  Zircotec seemed to be a more efficient, tidier and permanent solution.

I'm loathe to believe that the Zircotec has caused the overheating problem - as Jonathan says it moves the heat dissipation down to the exhaust and cat, but it was the only significant change that coincided with the emergence of this problem.

Neil

[anthonym]

Neil, any more comment on your experience with Zircotec during the last couple of years? 

I'm thinking about it for my R500K.

Anthony

 

 

p.s. In your op you muse about WC which was my first thought too reading that post, I am experimenting with Waterless Coolant in my 20 year old Ford Mondeo, there IS a huge pressure drop, based on releasing the cap.