HOW TO DO AN ADVANCED SEARCH.
Mon Jul 08, 2013 4:56 pm by Admin
For the benefit of 944Hybrids users there are two search functions available for you to use.
The purpose of this sticky is to explain the "Advanced Search" function because it is much more powerful and is the best choice when researching information.
When you log on to the site a list of options is shown in a line at the top of the page. One option is labelled "Search", use this option (NOT the search box lower down on the right).
After you click on the upper search option, a drop down box appears. At the bottom of this box is a radio button marked "Advanced …
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LS Overheating Issue
+9
Raymond-P
stu wright
JW1970
zeusrotty
spence
Hotrodz of Dallas
sharkey
Leva
rjarvis
13 posters
Page 2 of 3
Page 2 of 3 • 1, 2, 3
Re: LS Overheating Issue
The Forum folks have provided a lot of good info regarding the cooling system set up and the various pitfalls encountered when doing an LS swap. Hopefully you're on track with a solution.
As you mentioned, your LS is preowned and potentially a Pandora's box. From your thread, it does appear that you have replaced all the basic coolant related components eliminating many of the potential overheating causes.
One critical cooling issue not yet mentioned is your OIL.
Engine oil is responsible for up to 40% of engine heat dissipation. With the modified pans on these engines, the factory dip stick may NOT be a good indicator of oil volume.
BE SURE you have sufficient oil of the proper API grade for your driving application. GM says the LS motor takes 5.5 quarts with a filter change.
Food for thought...
As you mentioned, your LS is preowned and potentially a Pandora's box. From your thread, it does appear that you have replaced all the basic coolant related components eliminating many of the potential overheating causes.
One critical cooling issue not yet mentioned is your OIL.
Engine oil is responsible for up to 40% of engine heat dissipation. With the modified pans on these engines, the factory dip stick may NOT be a good indicator of oil volume.
BE SURE you have sufficient oil of the proper API grade for your driving application. GM says the LS motor takes 5.5 quarts with a filter change.
Food for thought...
Raymond-P- Posts : 373
Join date : 2013-06-29
Age : 68
Location : Beaver, PA
Re: LS Overheating Issue
I had the same challenges a few years ago. Chased everything. My issue was an under drive crank pulley.
968gene- Posts : 259
Join date : 2009-07-02
Re: LS Overheating Issue
968gene wrote:I had the same challenges a few years ago. Chased everything. My issue was an under drive crank pulley.
I never even thought about that, good mention. I do have a new gm harmonic balancer installed.
rjarvis- Posts : 61
Join date : 2020-01-15
Re: LS Overheating Issue
Raymond-P wrote:The Forum folks have provided a lot of good info regarding the cooling system set up and the various pitfalls encountered when doing an LS swap. Hopefully you're on track with a solution.
As you mentioned, your LS is preowned and potentially a Pandora's box. From your thread, it does appear that you have replaced all the basic coolant related components eliminating many of the potential overheating causes.
One critical cooling issue not yet mentioned is your OIL.
Engine oil is responsible for up to 40% of engine heat dissipation. With the modified pans on these engines, the factory dip stick may NOT be a good indicator of oil volume.
BE SURE you have sufficient oil of the proper API grade for your driving application. GM says the LS motor takes 5.5 quarts with a filter change.
Food for thought...
Hey Raymond - had mobil 1 5w-30 and 5.5 quarts in. I sent the oil off to blackstone labs the other week, nothing came back of much surprise. I am running a TPC pan which is also 5.5 quart
rjarvis- Posts : 61
Join date : 2020-01-15
Re: LS Overheating Issue
OK...check oil off the list.
So just to eliminate one other basic factor, what coolant blend are you running, 50/50 ethylene glycol?
There are many options here and some blends good for winter anti-freeze conditions are unfortunately terrible for summer boiling conditions.
You are already running synthetic oil which in itself reduces engine running temps.
As a last option, there are products are out there to improve the cooling efficiency of your system coolant. Below is a link to one from AMSOIL:
[You must be registered and logged in to see this link.]
DOMINATOR Coolant Boost advertises up to a 25 degree temp reduction. My experience with AMSOIL is their products do what they say.
So just to eliminate one other basic factor, what coolant blend are you running, 50/50 ethylene glycol?
There are many options here and some blends good for winter anti-freeze conditions are unfortunately terrible for summer boiling conditions.
You are already running synthetic oil which in itself reduces engine running temps.
As a last option, there are products are out there to improve the cooling efficiency of your system coolant. Below is a link to one from AMSOIL:
[You must be registered and logged in to see this link.]
DOMINATOR Coolant Boost advertises up to a 25 degree temp reduction. My experience with AMSOIL is their products do what they say.
Raymond-P- Posts : 373
Join date : 2013-06-29
Age : 68
Location : Beaver, PA
Re: LS Overheating Issue
Had a similar problem with my LS1 in 944. Change the plastic overflow tank to an aluminum one and run a 24 pound cap rather than the 16 llb. on the plastic tank. You cannot run any higher cap on the plastic tank because higher pressure will crack it. Put in hood vents to give heat an escape route, Engine bay is so filled that the entire front of the car becomes heat soaked. Lastly take off the nose and remove the metal shrouding and open up the air flow to the radiator. 944s were designed so that all air to the radiator goes underneath the car and then gets pulled upward by fans through the radiator. There is no direct air flow from car movement cooling the radiator. This will probably fix the fan problem.
In addition I purchased the vented nose piece that goes between the headlights and also opened two 6 inch by 2 inch openings in the bumper to increase air flow. My car on a 100 degree day now runs at a max of 210. Normally runs at 180 both examples with A/C running.
In addition I purchased the vented nose piece that goes between the headlights and also opened two 6 inch by 2 inch openings in the bumper to increase air flow. My car on a 100 degree day now runs at a max of 210. Normally runs at 180 both examples with A/C running.
porvette101- Posts : 3
Join date : 2014-03-24
Re: LS Overheating Issue
Great anylization I was thinking same thing .Sounds like airflow issue and possibly an air pocket in coolant would cause a big problem as well. LS motors are notorious for being a pain bleeding air out. Getting the hot air out of enginge bay helped mine out alot.porvette101 wrote:Had a similar problem with my LS1 in 944. Change the plastic overflow tank to an aluminum one and run a 24 pound cap rather than the 16 llb. on the plastic tank. You cannot run any higher cap on the plastic tank because higher pressure will crack it. Put in hood vents to give heat an escape route, Engine bay is so filled that the entire front of the car becomes heat soaked. Lastly take off the nose and remove the metal shrouding and open up the air flow to the radiator. 944s were designed so that all air to the radiator goes underneath the car and then gets pulled upward by fans through the radiator. There is no direct air flow from car movement cooling the radiator. This will probably fix the fan problem.
In addition I purchased the vented nose piece that goes between the headlights and also opened two 6 inch by 2 inch openings in the bumper to increase air flow. My car on a 100 degree day now runs at a max of 210. Normally runs at 180 both examples with A/C running.
stu wright- Posts : 312
Join date : 2009-07-19
Age : 61
Location : effingham illinois
Re: LS Overheating Issue
Just an update for anyone that ends up with similar issues:
Still keeping the test drives to about 20 miles. Have the 2 new fans installed and headers and y pipe of exhaust wrapped with heat wrap. I also got the trim piece that connects the radiator support to the bumper, and the piece that goes in front of the radiator.
Not too hot here, around 82f, car will cruise around 200, max 207 when pushing it a little harder.
Seems like it was an airflow issue. Waiting for it to warm up and test in some 90* weather. I think the setup would still benefit from some louvers to let heat out of the engine compartment.
Thanks for all the suggestions everyone!
Still keeping the test drives to about 20 miles. Have the 2 new fans installed and headers and y pipe of exhaust wrapped with heat wrap. I also got the trim piece that connects the radiator support to the bumper, and the piece that goes in front of the radiator.
Not too hot here, around 82f, car will cruise around 200, max 207 when pushing it a little harder.
Seems like it was an airflow issue. Waiting for it to warm up and test in some 90* weather. I think the setup would still benefit from some louvers to let heat out of the engine compartment.
Thanks for all the suggestions everyone!
rjarvis- Posts : 61
Join date : 2020-01-15
Re: LS Overheating Issue
Had my LS swap done last summer using the 951 radiator with TPC fans and shroud. The car overheated before I got to the gas station.
I replaced the radiator with a Wizard unit, replaced the thermostat with a 175 and cut in two hood vents. I made it until this summer. Highway driving temps were between 205-215. Stop and go temps were 215-225. However, track temps were as high as 253 (88 degrees outside). That was enough.
Removed all of it last month and put in the RH unit. Highway temps are now 186-188 (90 degree outside). Stop and go has not climbed above 193. Track day coming up so that will be the test. It will be fun to run the car without the temp worry.
I'm not sure where the issue was with the old unit. The Wizard unit is really nice (available if someone needs it) and appears to be more than adequate. Perhaps this confirms the issue is with the fans/shroud.
Resolved for now and the worry will move on to something else.
I replaced the radiator with a Wizard unit, replaced the thermostat with a 175 and cut in two hood vents. I made it until this summer. Highway driving temps were between 205-215. Stop and go temps were 215-225. However, track temps were as high as 253 (88 degrees outside). That was enough.
Removed all of it last month and put in the RH unit. Highway temps are now 186-188 (90 degree outside). Stop and go has not climbed above 193. Track day coming up so that will be the test. It will be fun to run the car without the temp worry.
I'm not sure where the issue was with the old unit. The Wizard unit is really nice (available if someone needs it) and appears to be more than adequate. Perhaps this confirms the issue is with the fans/shroud.
Resolved for now and the worry will move on to something else.
pipeman3rd- Posts : 18
Join date : 2020-02-14
rjarvis likes this post
Re: LS Overheating Issue
Hey pipeman
Can you post some pictures of the renegade setup? What do you use for fans with it?
I’m still having issues with overheating during this warmer weather.
Can you post some pictures of the renegade setup? What do you use for fans with it?
I’m still having issues with overheating during this warmer weather.
rjarvis- Posts : 61
Join date : 2020-01-15
LS overheating issue
Had similar issues on my swap. Ended up buying a set of Derale fans and had a shroud made. The Derale fans move a lot of air and my car runs at 190 deg in the Houston heat.
Hope this helps!
Hope this helps!
JW1970- Posts : 35
Join date : 2019-02-19
Re: LS Overheating Issue
The unit from RH came with a SPAL fan already mounted. Not sure what size but it was taller than the radiator. Thermostat was mounted and wired. I will try to get some pics tonight.
A very high quality unit.
A very high quality unit.
pipeman3rd- Posts : 18
Join date : 2020-02-14
Re: LS Overheating Issue
And there is no shroud on the RH unit.
pipeman3rd- Posts : 18
Join date : 2020-02-14
Re: LS Overheating Issue
I have a customer with the RH radiator and fan in his LS 944. It keeps it in the high 190's to low 200's until he turns on the ac. Then it will keep climbing until he has to shut off the car. It's ok on the highway, just not slow speed and traffic. I modified the radiator to be able to mount the stock 944 turbo fans, and now the car never gets above 200 in the worst traffic and 100+ degree outside temps.
Every single 944 LS I have built, I used the stock turbo fans and never had one overheat.
Every single 944 LS I have built, I used the stock turbo fans and never had one overheat.
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
Re: LS Overheating Issue
This is a very timely thread for my build too. I have a thicker aftermarket all aluminum rad from Griffin and I plan on using my 944S dual fans. If my fans are inadequate I need someone to tell me. I’ll be running AC but we don’t have crazy hot temps in PA..
Last edited by Raymond-P on Thu Aug 26, 2021 10:15 pm; edited 1 time in total (Reason for editing : Corrected brand of aftermarket rad.)
Raymond-P- Posts : 373
Join date : 2013-06-29
Age : 68
Location : Beaver, PA
Re: LS Overheating Issue
Raymond-P wrote:This is a very timely thread for my build too. I have a thicker aftermarket all aluminum rad from StayCool and I plan on using my 944S dual fans. If my fans are inadequate I need someone to tell me. I’ll be running AC but we don’t have crazy hot temps in PA..
Your S fans will work just fine. The fan shroud is slightly shorter than the turbo, but the fans themselves are the same as the turbo
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
Re: LS Overheating Issue
Hotrodz of Dallas wrote:Raymond-P wrote:This is a very timely thread for my build too. I have a thicker aftermarket all aluminum rad from StayCool and I plan on using my 944S dual fans. If my fans are inadequate I need someone to tell me. I’ll be running AC but we don’t have crazy hot temps in PA..
Your S fans will work just fine. The fan shroud is slightly shorter than the turbo, but the fans themselves are the same as the turbo
When you use turbo fans do you use the turbo shroud as well?
Going to look up fan and shroud part numbers.
rjarvis- Posts : 61
Join date : 2020-01-15
Re: LS Overheating Issue
rjarvis wrote:Hotrodz of Dallas wrote:Raymond-P wrote:This is a very timely thread for my build too. I have a thicker aftermarket all aluminum rad from StayCool and I plan on using my 944S dual fans. If my fans are inadequate I need someone to tell me. I’ll be running AC but we don’t have crazy hot temps in PA..
Your S fans will work just fine. The fan shroud is slightly shorter than the turbo, but the fans themselves are the same as the turbo
When you use turbo fans do you use the turbo shroud as well?
Going to look up fan and shroud part numbers.
Yes, I use the complete fan assembly from the 944
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
Re: LS Overheating Issue
Thanks Bob!!
Raymond-P- Posts : 373
Join date : 2013-06-29
Age : 68
Location : Beaver, PA
Re: LS Overheating Issue
You're very welcome
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
Re: LS Overheating Issue
Running the stock cooling system offers plenty of cooling capacity for these swaps. No need to spend a fortune on radiators and fans. Not running a shroud or an improper one is usually the crux of overheating issues. I fixed a couple of these cars by ditching aftermarket fans and installing the stock system. Personally I run the stock 944 radiator/fan system with no issue. Car hits 200 max in traffic on a hot day.
Leva- Posts : 82
Join date : 2020-04-04
Re: LS Overheating Issue
Leva wrote:Running the stock cooling system offers plenty of cooling capacity for these swaps. No need to spend a fortune on radiators and fans. Not running a shroud or an improper one is usually the crux of overheating issues. I fixed a couple of these cars by ditching aftermarket fans and installing the stock system. Personally I run the stock 944 radiator/fan system with no issue. Car hits 200 max in traffic on a hot day.
Not in Texas. We get 100-110 degrees daily during the summer. The stock radiator will not keep an LS cool here. Tried it on a couple of different builds. Stock fans is the only way I build them. Stock radiator no.
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
Re: LS Overheating Issue
Just ordered a set of turbo fans and shroud to use with the Wizard radiator just in case the RH system lets me down at the track. So far, even in stop and go traffic, it has not risen past 193 degrees in 90+ temps in NJ. I am hopeful that this is behind me. Track event in a few weeks will tell me.
When I spoke with RH they told me they are using a new radiator core that has more capacity than the previous unit (Ron Davis?). Not sure if anyone has heard the same?
When I spoke with RH they told me they are using a new radiator core that has more capacity than the previous unit (Ron Davis?). Not sure if anyone has heard the same?
pipeman3rd- Posts : 18
Join date : 2020-02-14
Re: LS Overheating Issue
pipeman3rd wrote:Just ordered a set of turbo fans and shroud to use with the Wizard radiator just in case the RH system lets me down at the track. So far, even in stop and go traffic, it has not risen past 193 degrees in 90+ temps in NJ. I am hopeful that this is behind me. Track event in a few weeks will tell me.
When I spoke with RH they told me they are using a new radiator core that has more capacity than the previous unit (Ron Davis?). Not sure if anyone has heard the same?
Where did you order from?
rjarvis- Posts : 61
Join date : 2020-01-15
Re: LS Overheating Issue
rjarvis wrote:pipeman3rd wrote:Just ordered a set of turbo fans and shroud to use with the Wizard radiator just in case the RH system lets me down at the track. So far, even in stop and go traffic, it has not risen past 193 degrees in 90+ temps in NJ. I am hopeful that this is behind me. Track event in a few weeks will tell me.
When I spoke with RH they told me they are using a new radiator core that has more capacity than the previous unit (Ron Davis?). Not sure if anyone has heard the same?
Where did you order from?
Ebay is where I get them if it didn't come on the car I'm building. Be sure they are the 6 blade fans and not the 3 blade. 85.5 and up are all 6 blade.
Hotrodz of Dallas- Posts : 615
Join date : 2015-10-31
Age : 65
Location : Dallas-Ft. Worth
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