Do I need a 3rd radiator?
Thread Starter
Rennlist Member
Joined: Apr 2010
Posts: 713
Likes: 6
From: NYC
Do I need a 3rd radiator?
I've searched and read numerous threads but I'm still on the fence about this. The 3rd radiator kit is inexpensive and looks simple enough for me to install. The larger question is do I really need it?
I live in the New York area so it isn't scorchingly hot here and I have never tracked my car (but I want to do a DE this summer). I do however sit in NY traffic and I can see my engine temps creep up. Never in the danger zone like when I had my 964 but still. I know that the radiator needs air blowing over it to work so I assume that when I do start rolling out of traffic it will do a better job of getting engine temps down than with just 2 radiators.
On the preventative side, I'm not sure that the radiator will help with problems like IMS or Bore scoring (my engine has been replaced twice by 2 former owners one for each issue). From what I underatand, bore scoring occurs at start up when the dissimilar metals expand at different rates.
So maybe I am answering my own question but I wanted to put it out there for the group to chime in on.
Thanks
-Mike B
I live in the New York area so it isn't scorchingly hot here and I have never tracked my car (but I want to do a DE this summer). I do however sit in NY traffic and I can see my engine temps creep up. Never in the danger zone like when I had my 964 but still. I know that the radiator needs air blowing over it to work so I assume that when I do start rolling out of traffic it will do a better job of getting engine temps down than with just 2 radiators.
On the preventative side, I'm not sure that the radiator will help with problems like IMS or Bore scoring (my engine has been replaced twice by 2 former owners one for each issue). From what I underatand, bore scoring occurs at start up when the dissimilar metals expand at different rates.
So maybe I am answering my own question but I wanted to put it out there for the group to chime in on.
Thanks
-Mike B
RL Community Team
Rennlist Member
Rennlist Member
Joined: Dec 2012
Posts: 7,605
Likes: 2,574
From: Atlanta
I would like to add a question on to yours:
- Will a third radiator slow the rise in oil temps at startup? (I drive in cold weather)
- Will a third radiator help prevent the oil temp spikes I see in summer?
BTW,yYou may be better off with just a lower temp thermostat that supposedly does reduce engine failures.... so they say. Lotsa stuff out there on that one.
Peace
Bruce in Philly
- Will a third radiator slow the rise in oil temps at startup? (I drive in cold weather)
- Will a third radiator help prevent the oil temp spikes I see in summer?
BTW,yYou may be better off with just a lower temp thermostat that supposedly does reduce engine failures.... so they say. Lotsa stuff out there on that one.
Peace
Bruce in Philly
Three Wheelin'
Joined: Aug 2016
Posts: 1,253
Likes: 271
From: Ohio
Is there a reason you think you need it? You don't track the car and your not having an issue currently. If there is a reason, let us know.
Also, a 3rd rad will increase the time it takes the car to get to temperature. On .1 cars, the goal should be to get them to temp as fast as possible as a preventative measure for ims/bs.
There not bad if you actually need them but if you dont, it could do more harm than good
Also, a 3rd rad will increase the time it takes the car to get to temperature. On .1 cars, the goal should be to get them to temp as fast as possible as a preventative measure for ims/bs.
There not bad if you actually need them but if you dont, it could do more harm than good
Racer
Joined: May 2008
Posts: 415
Likes: 6
From: Vancouver
https://www.hartech.org Engine Builds link....
Best source of info out there that i have read.............
Best source of info out there that i have read.............
Drifting
Joined: Feb 2012
Posts: 2,612
Likes: 424
From: Raleigh, North Carolina
The thermostat decides how long a car takes to warm up. You can have a football field sized radiator but as long as the thermostat is operating correctly, you will warm up just as fast as if you have no radiator at all. Radiators just keep your car from overheating. They don't affect your warm up time, as long as your thermostat is working properly.
Based on the OP's question, I don't think a third radiator will help him. First, if he hasn't overheated yet, there is no reason to fix what isn't broken. Second, a third radiator will only be of marginal help if the OP's worry is overheating in traffic. Sitting in traffic, there is little to no air across a radiator and the additional surface area for heat exchange will help, but in our cars, the radiators are down low, just above the hot pavement.
If there was a fan on the radiator, the answer might be different. But, living in a city with crappy roads, I would tend to look at the addition of a third radiator as just an additional opportunity for a rock or piece of debris to puncture my cooling system.
Based on the OP's question, I don't think a third radiator will help him. First, if he hasn't overheated yet, there is no reason to fix what isn't broken. Second, a third radiator will only be of marginal help if the OP's worry is overheating in traffic. Sitting in traffic, there is little to no air across a radiator and the additional surface area for heat exchange will help, but in our cars, the radiators are down low, just above the hot pavement.
If there was a fan on the radiator, the answer might be different. But, living in a city with crappy roads, I would tend to look at the addition of a third radiator as just an additional opportunity for a rock or piece of debris to puncture my cooling system.
Trending Topics
Three Wheelin'
Joined: Aug 2016
Posts: 1,253
Likes: 271
From: Ohio
The thermostat decides how long a car takes to warm up. You can have a football field sized radiator but as long as the thermostat is operating correctly, you will warm up just as fast as if you have no radiator at all. Radiators just keep your car from overheating. They don't affect your warm up time, as long as your thermostat is working properly.
I think you might be right on the warm up time but lower engine temps isn't always a good thing.
post #11 has great info on the cooling system, thermostats and 3rd radiators.
https://rennlist.com/forums/997-foru...ored-bore.html
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Talos Takes Your 991 Porsche 911 GT3 to the Next Level for a Cool $1.13 Million
Verdad Gallardo
9 Vehicles Porsche Helped Engineer that Aren't Porsches
Verdad Gallardo
9 Features and Characteristics That Only Porsche People Understand
Verdad Gallardo
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way
Joe Kucinski
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)
Verdad Gallardo
Porsche 911 GT3 S/C vs 718 Spyder RS: 10 Categories, One Winner
Joe Kucinski
This Builder Is Turning Heads With Its Slantnose 911 Creation
Verdad Gallardo
Porsche 911 GT3 Artisan Edition Pays Homage to Japanese Culture
Verdad Gallardo
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Verdad Gallardo
Drifting
Joined: Feb 2012
Posts: 2,612
Likes: 424
From: Raleigh, North Carolina
Adding a third radiator will not lower your operating temperature as long as your cooling system is operating correctly and your thermostat is opening and closing as it should. But, you have to be careful changing thermostats as well, since going to a cooler thermostat can have a detrimental affect on other systems.
It would seem on its face that going to a cooler thermostat would help the car, but that's rarely the case. Most cars are engineered to operate correctly from freezing temperatures all the way to desert-like conditions. Issues with overheating are almost always caused by a malfunction in the car, as opposed to some external condition.
Racer
Joined: May 2008
Posts: 415
Likes: 6
From: Vancouver
The thermostat controls the coolant flow rate through the engine. The hotter the coolant the more it opens the thermostat to allow more coolant to flow round the system and through the radiators
OP has a 2005 - a LTT will start the FLOW earlier - it will not make the car run at a lower temp.
If he is stuck in traffic in a city - he's not moving much so a 3rd radiator will do nothing - but at least creating more flow of coolant thru the system will take the heat away from the engine - especially #6 - which is prone to more heat as being furthest away from the coolant coming in etc - all described in Baz's post linked above and the Hartech info on their site.
Stuck in traffic his engine is getting hot and temps will climb - the lack of movement will not help the radiators cool much but at least with the coolant flowing - it will be circulating and drawing heat away from the engine - most importantly - thru the system and as soon as he moves off again - air will circulate thru the radiators and begin to cool the coolant in them.
OP has a 2005 - a LTT will start the FLOW earlier - it will not make the car run at a lower temp.
If he is stuck in traffic in a city - he's not moving much so a 3rd radiator will do nothing - but at least creating more flow of coolant thru the system will take the heat away from the engine - especially #6 - which is prone to more heat as being furthest away from the coolant coming in etc - all described in Baz's post linked above and the Hartech info on their site.
Stuck in traffic his engine is getting hot and temps will climb - the lack of movement will not help the radiators cool much but at least with the coolant flowing - it will be circulating and drawing heat away from the engine - most importantly - thru the system and as soon as he moves off again - air will circulate thru the radiators and begin to cool the coolant in them.
Drifting
Joined: Feb 2012
Posts: 2,612
Likes: 424
From: Raleigh, North Carolina
I'm not arguing with you. I just made some comments to clarify that I did not say going to a cooler thermostat would lower the car's operating temperature all the time. This is what many people think they are doing when they switch to a cooler Tstat. This is not the case. Also, people often think that going to a cooler Tstat is a fix to an overheating problem, when the overheating issue is actually caused by a malfunction somewhere else. In regular use, these cars should not overheat even in the worst traffic on a summer day. If a car overheats in those conditions (which the OP's car is not) then there is a malfunction somewhere that a new Tstat won't cure.
James
The thermostat controls the coolant flow rate through the engine. The hotter the coolant the more it opens the thermostat to allow more coolant to flow round the system and through the radiators
OP has a 2005 - a LTT will start the FLOW earlier - it will not make the car run at a lower temp.
A cooler thermostat doesn't affect the high end of a car's normal operating temperature because that upper limit is dictated by the car's cooling system as a whole. A cooler thermostat will extend warm up time, which allows the car to run at a suboptimal temperature longer than it should. It also allows this to happen when the outside temperature is low and the cooler thermostat is not restricting flow as early as the stock unit would have. This is rarely a good thing.
I have no idea how sensitive these engines are to engine and coolant temperature changes, but I do know that there are lots of cars that are extremely sensitive to coolant temperature being outside of a narrowly prescribed range. I would think that a DI engine would be particularly sensitive to this. I wouldn't go with a lower temperature thermostat unless I had both a ton of evidence showing that it wouldn't negatively affect my engine and a real need for that thermostat.
If he is stuck in traffic in a city - he's not moving much so a 3rd radiator will do nothing - but at least creating more flow of coolant thru the system will take the heat away from the engine - especially #6 - which is prone to more heat as being furthest away from the coolant coming in etc - all described in Baz's post linked above and the Hartech info on their site.
Agreed, but if the car is not overheating in traffic with two radiators, adding a third won't help because the car isn't having temperature spikes in the first place..
Stuck in traffic his engine is getting hot and temps will climb - the lack of movement will not help the radiators cool much but at least with the coolant flowing - it will be circulating and drawing heat away from the engine - most importantly - thru the system and as soon as he moves off again - air will circulate thru the radiators and begin to cool the coolant in them.
The additional radiator will have a measurable but marginal effect on his cooling capacity if there is no airflow across it. But if he isn't overheating now, then a third radiator is a fix to a problem that he doesn't have. Without a fan to move air across the third radiator, it won't have much effect on the system's efficiency during the periods where he's stuck in traffic, which is exactly the time he's concerned about.
OP has a 2005 - a LTT will start the FLOW earlier - it will not make the car run at a lower temp.
A cooler thermostat doesn't affect the high end of a car's normal operating temperature because that upper limit is dictated by the car's cooling system as a whole. A cooler thermostat will extend warm up time, which allows the car to run at a suboptimal temperature longer than it should. It also allows this to happen when the outside temperature is low and the cooler thermostat is not restricting flow as early as the stock unit would have. This is rarely a good thing.
I have no idea how sensitive these engines are to engine and coolant temperature changes, but I do know that there are lots of cars that are extremely sensitive to coolant temperature being outside of a narrowly prescribed range. I would think that a DI engine would be particularly sensitive to this. I wouldn't go with a lower temperature thermostat unless I had both a ton of evidence showing that it wouldn't negatively affect my engine and a real need for that thermostat.
If he is stuck in traffic in a city - he's not moving much so a 3rd radiator will do nothing - but at least creating more flow of coolant thru the system will take the heat away from the engine - especially #6 - which is prone to more heat as being furthest away from the coolant coming in etc - all described in Baz's post linked above and the Hartech info on their site.
Agreed, but if the car is not overheating in traffic with two radiators, adding a third won't help because the car isn't having temperature spikes in the first place..
Stuck in traffic his engine is getting hot and temps will climb - the lack of movement will not help the radiators cool much but at least with the coolant flowing - it will be circulating and drawing heat away from the engine - most importantly - thru the system and as soon as he moves off again - air will circulate thru the radiators and begin to cool the coolant in them.
The additional radiator will have a measurable but marginal effect on his cooling capacity if there is no airflow across it. But if he isn't overheating now, then a third radiator is a fix to a problem that he doesn't have. Without a fan to move air across the third radiator, it won't have much effect on the system's efficiency during the periods where he's stuck in traffic, which is exactly the time he's concerned about.
Three Wheelin'
Joined: Jul 2007
Posts: 1,649
Likes: 96
From: NJ
I'm always in favor of trying the easy/simple things first. I would inspect the radiators on your 911. In particular, I would check the outer vertical edges of each for leaves and other debris and carefully vacuum out the trash. I did this and found my oil tempts did improve slightly when it was hot outside. I remember in one of these forums, a poster installed a third radiator and after removing the bumper, discovered there was an enormous amount of debris between the A/C heat exchanger and the engine coolant heat exchanger, particularly around the outer areas. He did report an improvement in cooling but I always wondered which was more effective... the third radiator or the cleaning of the existing heat exchangers?
Last edited by Fahrer; Jan 26, 2017 at 04:17 PM. Reason: spelling
Thread Starter
Rennlist Member
Joined: Apr 2010
Posts: 713
Likes: 6
From: NYC
I appreciate everyone's input. I'm going to take the "if it ain't broke, don't fix it" approach and leave the cooling system as is. If I become a track junkie in the future I will revisit.
Even now I'm very careful about warming up the engine and usually shift around 3k rpms until the oil temp gets close to 200 degrees. It can take several miles of driving to get there. I assume that adding the 3rd radiator or thermostat would increase that time and like someone said that would increase the amount of time before the car gets up to optimal driving temp.
Now what oil is everyone using? I kid, I kid!
Even now I'm very careful about warming up the engine and usually shift around 3k rpms until the oil temp gets close to 200 degrees. It can take several miles of driving to get there. I assume that adding the 3rd radiator or thermostat would increase that time and like someone said that would increase the amount of time before the car gets up to optimal driving temp.
Now what oil is everyone using? I kid, I kid!
Thread Starter
Rennlist Member
Joined: Apr 2010
Posts: 713
Likes: 6
From: NYC
I recently cleaned out my radiators before adding some DIY Home Depot grills. I removed about a 1/2 pound of crap on each side.
I'm always in favor of trying the easy/simple things first. I would inspect the radiators on your 911. In particular, I would check the outer vertical edges of each for leaves and other debris and carefully vacuum out the trash. I did this and found my oil tempts did improve slightly when it was hot outside. I remember in one of these forums, a poster installed a third radiator and after removing the bumper, discovered there was an enormous amount of debris between the A/C heat exchanger and the engine coolant heat exchanger, particularly around the outer areas. He did report an improvement in cooling but I always wondered which was more effective... the third radiator or the cleaning of the existing heat exchangers?
Racer
Joined: May 2008
Posts: 415
Likes: 6
From: Vancouver
Yes all good points - clean the Rads and is the coolant old / original - how about a new coolant and the LTT - which i would add - read baz/ Hartech info - well known issue with these cars.
What about water pump - a few broken impellers - apart from not being good - wold cut down flow - this is considered a preventative maintenance item.
In summary - generally you don't see the temp climb sitting in traffic on a normal day.
I would - if not done already or recently - install LTT - new water pump and new coolant - then you are good to go for the next - 4-5 yrs on that.
What about water pump - a few broken impellers - apart from not being good - wold cut down flow - this is considered a preventative maintenance item.
In summary - generally you don't see the temp climb sitting in traffic on a normal day.
I would - if not done already or recently - install LTT - new water pump and new coolant - then you are good to go for the next - 4-5 yrs on that.