Engine Bay Temp Data Logging Thread

[gluaisrothai]

What fan and thermostat did you wind up using?

I used an old 12v avionics cooling fan I had lying around. Like this:

Cyclone 100 - 1 Port Blower (14VDC or 28VDC)

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You might find one cheap on eBay, lots of versions and most have the 5/8” output.

And this is the thermostat: https://www.amazon.com/gp/aw/d/B0C282MRM6?psc=1&ref=ppx_pop_mob_b_asin_title

 

[daneo]

Some findings to share. I was able to get my lithium battery to reach shut-down temperatures by doing 8 hours of low range in 90f+ temps. Burned through half a tank of gas in 50 miles of trail. It took all day to reach that temp and it shut off just before reaching camp. This was with a moderately loaded 5th gen 4Runner (driver-only, GFC RTT, TrekBoxx, fridge, Slee sliders, aluminum front skid, winch) with the 4.0 v6.

A couple take-aways:

Airflow across the radiator, engine, and exhaust is paramount to keeping under-hood cool. Stops had a large effect on bumping up the measurements. Driving at highway speeds in similar conditions, the battery barely peaked into the triple digits. The 200’s bigger engine and tighter bay could exacerbate the effect as well as heavier loaded vehicles and mods that block airflow (bumpers, lights).

High range can help keep temps down. Less fuel burning per meter of forward movement and thus airflow. Under similar trail conditions, the battery peaked at ~115f when I ran mostly 4hi.

Internal battery temps take a long time to reach the ambient under-hood temps. It is a pretty hefty brick to heat up after all.

Note the time in the picture. We were on trail by ~10am and the temperature asymptotically approached 140f over the course of the day. I popped the hood at camp and it took about an hour for the battery to recover. Did much better the rest of the trip when more high range was used.

 

[gluaisrothai]

Some findings to share. I was able to get my lithium battery to reach shut-down temperatures by doing 8 hours of low range in 90f+ temps. Burned through half a tank of gas in 50 miles of trail. It took all day to reach that temp and it shut off just before reaching camp. This was with a moderately loaded 5th gen 4Runner (driver-only, GFC RTT, TrekBoxx, fridge, Slee sliders, aluminum front skid, winch) with the 4.0 v6.

A couple take-aways:

Airflow across the radiator, engine, and exhaust is paramount to keeping under-hood cool. Stops had a large effect on bumping up the measurements. Driving at highway speeds in similar conditions, the battery barely peaked into the triple digits. The 200’s bigger engine and tighter bay could exacerbate the effect as well as heavier loaded vehicles and mods that block airflow (bumpers, lights).

High range can help keep temps down. Less fuel burning per meter of forward movement and thus airflow. Under similar trail conditions, the battery peaked at ~115f when I ran mostly 4hi.

Internal battery temps take a long time to reach the ambient under-hood temps. It is a pretty hefty brick to heat up after all.

Note the time in the picture. We were on trail by ~10am and the temperature asymptotically approached 140f over the course of the day. I popped the hood at camp and it took about an hour for the battery to recover. Did much better the rest of the trip when more high range was used.

View attachment 3688325

I believe a cooling shroud could help extend the life of a standard lead acid battery in underhood applications. That’s why Cessna does what they do.

 

[2021 LC200]

Anybody considered wrapping the exhaust headers to reduce under hood temps?

Maybe the access is terrible in the 200? Also under wrap corrosion is maybe a concern, although I believe that is more an issue for the rest of the exhaust.

This I undertand is a picture of the right hand side header on a Lexus 3UR-FE, which is no doubt the same on LC or LX versions of the 200. Would be nice to wrap it until the connection to the exhaust or cats, what ever comes next.

This is indicated as passenger side for a LX570 2008 to 2021

 

[bloc]

Anybody considered wrapping the exhaust headers to reduce under hood temps?

Maybe the access is terrible in the 200? Also under wrap corrosion is maybe a concern, although I believe that is more an issue for the rest of the exhaust.

View attachment 3689058

This I undertand is a picture of the right hand side header on a Lexus 3UR-FE, which is no doubt the same on LC or LX versions of the 200. Would be nice to wrap it until the connection to the exhaust or cats, what ever comes next.

View attachment 3689061

This is indicated as passenger side for a LX570 2008 to 2021
View attachment 3689073

View attachment 3689074

A good ceramic coating would be a much better long-term solution. As it is the stock waffle shielding is actually quite good at shutting down radiant heat.. it’s just a lot of engine, and almost all of the air under the hood went through the hot radiator to get there.

 

[2021 LC200]

A good ceramic coating would be a much better long-term solution. As it is the stock waffle shielding is actually quite good at shutting down radiant heat.. it’s just a lot of engine, and almost all of the air under the hood went through the hot radiator to get there.

Thanks Bloc.

I was looking into starter change out at say 150k miles and am tempted to get in there now at 35k miles to loosen and apply high temp/copper anti seize to facilitate exhaust and exhaust manifold removal. Would not be a stretch to take out the manifold and coat them as long as I do it all correct and not mess up anything (i.e. break any bolts or electrical connectors or otherwise, get new gaskets and bolts, etc.).

I may do this in the fall and also drain and replace the coolant in the process.

Regarding make up torque, when using anti seize it seems you should back off by around 25%. I am thinking of marking bolts with a white liquid marker and use that as well. Any insights/learnings around this?

 

[bloc]

Thanks Bloc.

I was looking into starter change out at say 150k miles and am tempted to get in there now at 35k miles to loosen and apply high temp/copper anti seize to facilitate exhaust and exhaust manifold removal. Would not be a stretch to take out the manifold and coat them as long as I do it all correct and not mess up anything (i.e. break any bolts or electrical connectors or otherwise, get new gaskets and bolts, etc.).

I may do this in the fall and also drain and replace the coolant in the process.

Regarding make up torque, when using anti seize it seems you should back off by around 25%. I am thinking of marking bolts with a white liquid marker and use that as well. Any insights/learnings around this?

Personally? I wouldn’t do all of that. You could be getting into territory where the potential for human error is canceling out or even defeating the potential benefit of this extra maintenance. In your case these systems are working great, and Toyota isn’t known for issues caused by fluids degrading on their schedule. 10k OCI and lifetime transmission being the notable exception, but there are marketing pressures for that stuff.