Aftermarket [$150] replacements are ALMOST as good as oem if you don't need 100% of the as designed cooling effectiveness.Those that live in temperate climates where 90F is rare or not prolonged.
A new 90% rad is better than an old beat up 80-70%-50% rad.Finding some that will fit and yield 105-110% is a real challenge!
Don't assume that thicker is always better.
Most problem have to do with the foam surround [lack thereof] allowing air to sneek around the rad and hot air from engine compartment blending back around to the front of rad.A MORAL story:We received a Q from another independent shop that was still overheating after a rad replacement. The customer said they also replaced the thermostat [visible new RTV] and hoses.
After a few hours of measuring and refilling we tore into the system: Theromstat was a generic deeper unit "made to fit" by hammering it in and bending it so that it was always open a little, replaced it and the problem got a little better, pulled water pump old but serviceable, hoses removed , then the radiator...........jammed [sucked] way inside was a plastic end cap used to seal the rad inlet for shipping.
The coolant flow was restricted by 50% or more, at high rpms the pressure forced the plastic to deform and flow better........at idle little flow.
Took 4 hours to solve this. After all it was a brand new radiator from a known company.
Also the aux fan had a plastic bag wrapped around it burning out the motor. Plus the thermo clutch on the mechanical fan was weak.
Lots of minor problems to sequentially solve but the plastic end cap was the COUp de GRAce.
92Q Overheated!
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Must read:http://www.stewartcomponents.c...s.asphttp://www.stewartcomponents.c...port/
http://www.usradiator.com/diagnostic.htm
"We've learned, for example, that core design has more bearing on temperature drop than material (copper- brass verses aluminum). We've also learned that 2 rows of 1-1/4" aluminum tubes had only a 3-degree advantage over 4-rows of 1/2" brass tubes at 65 m.p.h and a 2-degree disadvantage at idle. Given the added core thickness of the aluminum radiator we had expected a greater temperature drop...but, it wasn't there."http://www.usradiator.com/testing.htm
"Aluminum radiators, especially with plastic tanks, tend toprecipitate aluminum phosphates and silicates out on the inner surface of the tubes if common commercial coolants(like Prestone green) are used in combination with hardwater.
The precipitates come from the hotter heat rejectingsurfaces like aluminum cylinder heads and are moresoluble at higher temperatures. They tend to form inside the radiator especially as the corrosion protection package in the coolant weakens. The thermalefficiency of the radiator is reduced significantly as the process progresses.
Many European auto manufacturers specify phosphate,nitrate, and amine free coolants for that, and, a fewother reasons."
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!http://www.eng-tips.com/gviewt...61247
"Black paint will cause additional problems:
1. Acts as a small additional resistance to conductive heat-transfer ie. lowers heat-transfer performance;
2. Paint can clog the micro-louvers in the multi-louver fins, & will limit the designer's ability to create high-performance louvers... ie. lowers heat-transfer performance.
3. Paint never completely coats the centre sections of the core, leading to areas of higher corrosion potential for copper-brass radiators. (In fact unpainted copper-brass radiators last 30% longer than painted copper-brass units... interesting...)"
http://www.usradiator.com/diagnostic.htm
"We've learned, for example, that core design has more bearing on temperature drop than material (copper- brass verses aluminum). We've also learned that 2 rows of 1-1/4" aluminum tubes had only a 3-degree advantage over 4-rows of 1/2" brass tubes at 65 m.p.h and a 2-degree disadvantage at idle. Given the added core thickness of the aluminum radiator we had expected a greater temperature drop...but, it wasn't there."http://www.usradiator.com/testing.htm
"Aluminum radiators, especially with plastic tanks, tend toprecipitate aluminum phosphates and silicates out on the inner surface of the tubes if common commercial coolants(like Prestone green) are used in combination with hardwater.
The precipitates come from the hotter heat rejectingsurfaces like aluminum cylinder heads and are moresoluble at higher temperatures. They tend to form inside the radiator especially as the corrosion protection package in the coolant weakens. The thermalefficiency of the radiator is reduced significantly as the process progresses.
Many European auto manufacturers specify phosphate,nitrate, and amine free coolants for that, and, a fewother reasons."
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!http://www.eng-tips.com/gviewt...61247
"Black paint will cause additional problems:
1. Acts as a small additional resistance to conductive heat-transfer ie. lowers heat-transfer performance;
2. Paint can clog the micro-louvers in the multi-louver fins, & will limit the designer's ability to create high-performance louvers... ie. lowers heat-transfer performance.
3. Paint never completely coats the centre sections of the core, leading to areas of higher corrosion potential for copper-brass radiators. (In fact unpainted copper-brass radiators last 30% longer than painted copper-brass units... interesting...)"
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maxnix
- Posts: 22627
- Joined: Mon Jul 22, 2002 8:11 pm
- Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45
Thanks, I will read and contemplate.
I thought this comment is a good reason not to use anything but an aluminum radiator with an aluminum engine like the VH45DE:
the pro's of al radiators lie in lower weight and nowadays lower production costs when produced in large quantities. another consideration might be that when you have an al-engine you don't have a potential between radiator and engine that could promote corrosion due to different materials.
I thought this comment is a good reason not to use anything but an aluminum radiator with an aluminum engine like the VH45DE:
the pro's of al radiators lie in lower weight and nowadays lower production costs when produced in large quantities. another consideration might be that when you have an al-engine you don't have a potential between radiator and engine that could promote corrosion due to different materials.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
The radiator sits in rubber isolated insulated mounts! The only path is thru the coolant electrochemically......even the thermoswitch is isolated from ground.
Failure to change coolant hoses feeding the rad can allow current thru spiral wrap wire IF it get abraded or oxygen break down of rubber.
Most rad failures [besides plastic end tanks] are from using cheap solder on aluminum fins to the tube.
Failure to change coolant hoses feeding the rad can allow current thru spiral wrap wire IF it get abraded or oxygen break down of rubber.
Most rad failures [besides plastic end tanks] are from using cheap solder on aluminum fins to the tube.