Reco'ing/Replacing the 260z coolant system

[stevo_gj]

Hey guys,

 

I've recently put an air conditioning unit into my 260z and i've found that the engine is running quite hot when I have the aircon on.

 

My mechanic has pointed out to me that the whole system is quite old and weak. I am thinking I need to replace the radiator and add an electric thermo fan in the location of the mechanical one.

 

I was also thinking it might be worth adding a thermo fan in between the condenser and the radiator to improve airflow.

 

My questions are:

 

What options do I have regarding replacing the radiator, and what are peoples opinions on them? I have read that you can get it reconditioned for around the $400 mark. Is this the best option for peace of mind?

 

What is everyone's opinions on thermo fans? Will running an additional fan in front of the radiator but behind the condenser show an improvement?

 

Cheers,

 

Steve

 

Edit: I am currently running the stock mechanical fan.

[Riceburner]

Try fitting a lower temp thermostat(170deg) and see what that does, for $9 it's worth a shot! Then fit thermo fan to help when car isn't moving. The a/c condenser will give off 10-12deg above ambient temp... so on a 30 deg day your radiator is getting 40deg air onto it!

[Riceburner]

Think you might even be able to get a 160deg t/stat.

[stevo_gj]

What is the job of the thermostat? I thought that the mechanical system didn't changed based on engine temperature.

[Riceburner]

It restricts water flow through cooling system, I have a 170 deg in my 240 with l28 and on 35deg days it runs a bit above 1/3 on temp gauge. No air con though.... Or thermo fan. Original radiator, you could also drop the coolant and backflush the cooling system to remove any sludge that builds up over time.

[Riceburner]

With standard t/stat it used to run at 1/2 most of time and a bit above on warmer days. New lower temp t/stat made more of a difference than i thought it would.

[stevo_gj]

With standard t/stat it used to run at 1/2 most of time and a bit above on warmer days. New lower temp t/stat made more of a difference than i thought it would.

 

Well I might just try that. That's what mine runs at currently, except its half on normal days and a bit above when aircon is on. Any idea on part numbers or where I would order one?

[Riceburner]

Try bursons or autobarn ask for dayco brand 170deg t/stat to suit l24 or l28 whatever engine you have, they should have them on the shelf. Also when you get it home fill a coffee cup with freshly boiled water, drop the t/stat in it and watch it open (the centre section should drop down, it's easy to see). Just pays to check them, I've had tridon brand t/stats that didn't open straight out of the packet!!   

[Riceburner]

Sorry just checked my notes, it's a 160deg!!!  So just ask for a 160 t/stat. 

[260Coupe]

Steve

Give the radiator a good clean with radiator flush to de-scale and then flush out with a high pressure hose.

I refitted the aircon to my Zed and installed 2 x 9" thermo fans in front of the condensor and triggered the relay off the compressor actuator wire.  Turn on the aircon and the two fans start up and run continuously. Even on a day of 42 deg the temp never gets over half way. I also have 2 x 12" fans behind the radiator which are for normal cooling but find they only start up after sitting idling for some time

 

You can get these fans off ebay (yep they are Chinese but are great for the price)  they work really well and only draw around 4 amps so you won't be overloading the electrics. 

 

http://cgi.ebay.com.au/9-INCH-THERMO-FAN-BRAND-NEW_W0QQitemZ310193910905QQcmdZViewItemQQptZAU_Car_Parts_Accessories?hash=item4838ff7479

[C.A.R.]

+1 on the Tridon T/stats - total garbage!

 

Since your in Qld Steve, have you thought about running no thermostat at all?

You simply remove the 'guts' of the old t/stat & retain the outer 'ring' of the s/stat (so that coolent is still pushed to the back of the head). This may help the engine running cooler from start-up.

 

Also, I dare say your using a Eytholene Gycol based (green coloured) coolent?

This stuff is absolutely horrible for thermo-effectciy of an engine.

Backflush your cooling system, then add a bottle of Redline 'Water Wetter'.

It's awesome stuff & I've never gone back to the horrible old Glycol based coolents...

[dazzed]

hey Steve when you say hot , what is hot? all engine run hot how hot? does your radiator have a full surround fan shroud, if there is no shroud the fan will not draw air through the radiator, if your engine is running hotter than half on the gauge and has a standard 82 degree thermostat in it putting a cooler thermostat will not help because over half on the gauge the thermostat is open anyway putting a cooler thermostat in will only open earlier than later once open thats it its open ,sorry lurch had to throw it in but the redline is the way tro go for sure

[Scoota G]

There's also the thought that you can take the radiator in a get the tanks removed for a proper mister sparkle clean. My radiator guy does them for $88.

[.]

I am no expert I am only repeating what I read last night. But I read that removing the thermostat can make the system less efficient as the coolant moves too quickly and doesn't allow proper heat sink.

 

I guess thats why 3 core radiators are better because the coolant spends longer in the radiator.

[stevo_gj]

Thanks for the input guys.

 

I've posted a picture below that should answer your questions. Currently it runs like the middle one during normal driving around town, and the right one when the aircon is on. I am under the impression that this was a bit hotter than I would like and that it should look like the left one.

 

I think that Daniel is correct, the t/stat should already be fully open when its running during normal operation so I don't see how making it open sooner will make much of a difference except for very short drives.

 

I currently have the stock mechanical fan with the original shroud.

 

You are correct Lurch I am using the green stuff.

 

I just found these on ebay, I measured up the condensor and I believe that I should be able to put this in front of it quite easily:

 

http://cgi.ebay.com.au/TWIN-THERMO-FAN-10-X-10-BRAND-NEW_W0QQitemZ310194680395QQcmdZViewItemQQptZAU_Car_Parts_Accessories?hash=item48390b324b

 

I was thinking I would do the following:

 

-"Give the radiator a good clean with radiator flush to de-scale and then flush out with a high pressure hose."

-Add the Redline 'Water Wetter'

-Install these ebay thermo fans in front of the condensor

-Depending upon success of previous step, install a single large thermo fan in place of original mechanical fan using the existing shroud.

 

How does this sound?

[stevo_gj]

This is the same set of thermo fans but also comes with relays and thermostats, think it's worth the additional $40 for those components?

 

http://cgi.ebay.com.au/TWIN-THERMO-FAN-10-X-10-THERMOSTAT-WIRING-KITS_W0QQitemZ310194577671QQcmdZViewItemQQptZAU_Car_Parts_Accessories?hash=item483909a107

[260Coupe]

Steve

 

Leave the thermosat in ........removing it will only mask the problem and create others.

My Zed ran at the same temp (as per your third figure) around 90 + deg on the gauge until I fitted the thermo fans in front of the condensor. Once I fitted the thermo fans the problem was solved , temp runs at a constant 82 deg even when stuck in traffic on the hottest days.

 

 

[Zedman240®]

I'd go with Daniel and Allan, leave the thermostat in. Late model cars now with clutch and electric fans have the mandatory electric fan with the AC. The fan for the condenser should be on always when the AC is on for the air conditioning system to work efficiently. All the AC does is remove heat from inside the car and dump it outside hence why the condenser needs a fan to blow air through it to remove all the heat. I won't go into detail on how air conditioning works so I won't bore you to tears. Try to mount fans that cover most if not all of the condenser for it to work well. The third pic of the temp gauge is a little hot for my liking but as Allan said, mount the fans and there shouldn't be a problem.

[stevo_gj]

Cool thanks guys, I'll do as you suggest and put the twin thermo fans in front of the condensor.

 

Still looking for some guidance relating to that ebay auction. I have no idea about the costs of relays, temp sensors and the like that he is including with that auction. Does anyone think it's worth buying the $90 package as opposed to buying the $50 one and purchasing those bits separately?

[Mr240z]

Steve, If your buying themo fans buy Davis Craig once and don't get court with Ebay crap ones.

 

They cost heaps but if you buy the right ones first you'll be happier in the long run.

 

Ebay sells sh$t when it comes to no thrills electric parts.

 

http://www.daviescraig.com.au/Thermatic_Fans-list.aspx

[260Coupe]

Steve, If your buying themo fans buy Davis Craig once and don't get court with Ebay crap ones.

 

They cost heaps but if you buy the right ones first you'll be happier in the long run.

 

Ebay sells sh$t when it comes to no thrills electric parts.

 

http://www.daviescraig.com.au/Thermatic_Fans-list.aspx

 

 

I beg to differ.........I have four of these fans fitted to my zed and the first two installed have worked flawlessly for the past three years (behind the radiator). The second pair installed a year ago for the aircon condensor and these have also performed without failure.

Yes I agree that Davies Craig are excellent however they draw massive current and they are not that much more efficient than the "cheap n cheerful"

I have a DC 14" fan in my race car (Sports 2000 Roadster) and whilst it works well, at $240 it was far more expensive , sucks 15-20 amps and no better than the fans on ebay.

 

I suppose in the end it is you choice