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In my opinion, Toyota intentionally left that gap unsealed. The hood gap over the headlights, while unsightly... appears to function for heat extraction. If you hold your hand across the gap area after driving the vehicle, the heat escaping through the gap from the engine bay will be detectable. Significant heat extraction is not detectable elsewhere, not to the rear of the hood, the front grills or under the vehicle due to the aero cladding that covers most of the engine bay. In my experience, water intrusion through the gaps due to rain or car washing has been minimal.
Heat will go up, wherever it can. Venting heat over the plastic of the headlamps makes no sense. Heat cycling plastics means the plastic will crack/degrade sooner.
 

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White 2021 RAV4 LE / FWD with XP Trail Package
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Heat will go up, wherever it can. Venting heat over the plastic of the headlamps makes no sense. Heat cycling plastics means the plastic will crack/degrade sooner.
Heat will definitely rise, but it needs a pathway for escape. Excess heat build-up in the engine bay can cause damage to the electronics, the computer, the battery, and degrade wiring. I began studying the gap issue on my vehicle after first noticing this thread. Obviously, Toyota left gap seals off North American models with the naturally aspirated gas engine for a reason. And somehow, I don't think they were cost cutting or it was a supply chain issue. The only logical explanation for both the excess gap designed in over the headlamps and the lack of seals would be heat extraction. Clearly, tooling and production costs to add heat extraction vents to the top of the hood would have been much higher than venting through a gap designed in over the headlights.

The real mystery is: why would Toyota also make gap seals available through their parts departments, and reportedly include them standard on European models? And if gap seals were intended on all models, why design in the large gap over the lights? Anyways, I'm leaving the gaps on my RAV4 unobstructed for heat extraction. Water intrusion has not been an issue.

As for venting heat over the the head lamps... I doubt it will reduce the life span of the headlamp assembly. The headlight internal fixture is made of a sturdy thermoplastic material designed to withstand heat and humidity; The outer lenses are predominantly formed from polycarbonate resin. The versatile polymer is well-suited for automotive lighting applications because of its thermal stability, impact strength, clarity, and heat resistance.
 

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I'm still going back and forth on this, like many others I'd assume. For now they'll stay... my '21 Highlander Hybrid came with them factory installed (Kentucky build), which eases my mind on keeping them in...
 

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Heat will definitely rise, but it needs a pathway for escape. Excess heat build-up in the engine bay can cause damage to the electronics, the computer, the battery, and degrade wiring.
So wait a sec. They designed that gap to allow heat to escape? Not much area there for flow, I don't see where that small area will allow heat convection to carry enough heat out to keep temps low in the engine bay. Simply test it, park a thermocouple somewhere in the engine bay, connect it to a temp reading module, measure engine bay temps with and without the gaps. Bet ya no diff can be noticed.

But then later they design a gasket to plug the gap? I suspect all the extra dirt that enters the engine bay from driving with open gap is more detrimental to wiring and sensors than the heat of the engine at idle or after turn-off.

If things getting hot is an "issue", which I don't think it is, then why do many/most Lexus vehicles place a heat trapping cover over the top of the engine? Trapping heat is bad, yes?

Over temp or too low temp, and heat cycling, are THE two main causes for accelerating the failure of the items you mentioned.

Getting water in engine bay is a loaded topic. Nylon likes water, without water nylon becomes brittle and breaks like glass. Other plastics might be sensitive to the ph of the water. The materials chosen however seem to be the best choice to make a reliable long lasting vehicle.

And then ask another question, 4.5gen Rav4 is the only vehicle they deigned to have air gaps over the headlamps (needed to let heat out)? No other vehicle Toyota makes would benefit from same gaps?
 

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Installed them today.
My method:
dry fit the pieces, read 1-2-3 here, dry fit, then go.

1) damp cloth (hot water), wipe the lens area clean.
2) a drop or two rubbing alcohol on dry rag, just wipe the area clean, wave hands (wind) to evap the alcohol. Wait 1min.
3) install rear to front, there's an obvious triangle cut on end-edge of rubber, and a slight triangle sticking up from the lens, align rubber cut into the little lens triangle (butt up to), move slowly, try not to pull-stretch as you go otherwise it will land long on the far end.

Some arguments in this thread that say Hybrids have them but ICE do not. But the benefits mentioned for ICE not to having them are not benefits Hybrids should have? Would be good to get an official statement from Toyota.

I installed them, hopefully it cuts down on the dirt entering engine bay.
 

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I installed those oem toyota weatherstrips a week or so ago. They're a little pricey now. I paid $18 each from mcgeorge toyota, msrp is $27, and your local dealer could charge even more. Even after installing those, there's still about a 4" gap farther up the hood, which I've seen mentioned in this thread or another thread on this topic.

I decided to seal up that small gap today, and the stuff I used seems pretty good quality, and could be an alternative to the oem toyota seals which have gone up in price. $1.55 a foot and free shipping, height and width are basically the same as the oem toyota seals. Automotive RV Marine Exterior Hollow D Rubber Door Hatch Weather Strip w/ Seal (original link was broken, fixed now)
There wasn't really a good sealing surface behind the headlights, so I attached it to the hood. oem toyota seals are 17" long, if you want to cover the extra gap that I did today, you'll need 23" for each side.

Living in Maine I'm not too worried about trapping heat, engine compartment should be able to withstand the heat produced.
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the hood/headlight gap is designed to be there, (inc the rubber gap) to assist with air circulation in the engine bay, as this area is fully enclosed via the under body cowling...that said, the gap's could be uneven depending on factory build quality on the day...

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OK, this is too funny.

I just came back online to R4W site and was looking for this thread, but it was in my Alerts notice that someone posted to it.

I wanted to add an update.

I had added the gaskets some time ago (post #427). My observations are this, 1) way less dirt in the engine bay (which was my goal), and 2) the outside temp reading (in the dash) now reads higher than actual outside temp.


Rav4-Lim said:
Heat will go up, wherever it can. Venting heat over the plastic of the headlamps makes no sense. Heat cycling plastics means the plastic will crack/degrade sooner.
Uh, yeah, don't think they really care about that with plastic intake manifolds, plastic valve covers, plastic air cleaner box, etc in extremely high heat areas under the hood.
Well, I think you have a half point to make, but missing some facts. Not all plastics are the same, and not all like to heat cycle. The plastics in the engine bay are far different than the plastics outside the engine bay, and certainly for acrylic headlamp plastic.

I suspect, only from looking online, most of the stuff in engine bay is thermoset polyester (or the like), and the stuff outside is just formed thermoplastic.


the hood/headlight gap is designed to be there, (inc the rubber gap) to assist with air circulation in the engine bay, as this area is fully enclosed via the under body cowling...that said, the gap's could be uneven depending on factory build quality on the day...
It's not really "fully" enclosed. There's some wheel-well area and wide open to the ground from the exhaust on down for airflow. I am 100% certain the operation of the 2.5L ICE in the Rav4 is not relying on two small gaps to provide "required" cooling of the engine bay.

I simply did not do it, but if someone wants to test it, place a thermocouple in the engine bay and monitor temps w/o the gaskets before installing them, then monitor the after. I suspect no big diff to be had. These days they make inexpensive bluetooth temp sensors w/ phone app, etc.

Although there's plenty of places for dirt & dust to enter, it seems I have less dirt in the engine bay with the gaskets. Not a scientific measurement, just eyeballing it.
 

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Everything toyota does is intentional. There must have been a need to change air flow, lower wind noise, etc. I wouldnt assume you can know better. Just leave it that way. Just my opinion of course. Flame suit engaged
 

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Sure, but a lot of it is to optimize cost or weight. If the side effects are deemed acceptable, they will do pretty much anything for those goals. The missing tow hooks are a perfect example.
Those “tow hooks” are only added to vehicles that go through oceanic shipping as to secure them. They are added just for this purpose alone. Most vehicles will not have them. My last two vehicles before this one didn’t have tow hooks either.
 

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Those “tow hooks” are only added to vehicles that go through oceanic shipping as to secure them. They are added just for this purpose alone. Most vehicles will not have them. My last two vehicles before this one didn’t have tow hooks either.
My last subaru built in Indiana had front and rear tow hooks, I highly doubt they are ONLY found on cars that go through oceanic shipping.
 

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Heat will definitely rise, but it needs a pathway for escape. Excess heat build-up in the engine bay can cause damage to the electronics, the computer, the battery, and degrade wiring.

The pathway 🙂

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🤔

Think part of the reason was to address some of the hood vibration mentioned at speed, along with water intrusion.

both of which never experienced, was hard to understand what people were talking about. 🤔

the video address some of the issues that were corrected

Note the screen shot..looks like no rubber sealing between the hood and led light assemblies


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Sure, but a lot of it is to optimize cost or weight. If the side effects are deemed acceptable, they will do pretty much anything for those goals. The missing tow hooks are a perfect example.
Correct.

Is having a boat load more dirt in the engine bay "acceptable"? From Toyota viewpoint that's probably a end-user issue, as in "clean your engine bay more often".

Fine dirt/dust (and bugs) will make it's way into everything. Having less dirt in the engine bay is by comparison, better.

There will still be plenty of dirt coming in, the front grill is big and wide open. I just noticed there's less dirt sitting around on the upper surfaces that are closer to the headlamps, like air filter box, fuse box, battery, plastic intake tube, etc etc.

The 4.5gen Rav4 is too new to know what the long term problems will be. Surely what will be issues from "Toyota knows best" will come out over the next 15yrs and 300kmi. And when "Toyota knows best" changes the design just 4-5yrs later, the whole cycle of issues starts over again.

The logic seems to be , "it's for cooling". Wouldn't not having the gaskets there also help cool the Hybrid too? Was it OEM std to have them on the Hybrid to just keep dirt out?

Whatever the reason, nobody seems to know, and Toyota not really published anything as to why.
 

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The logic seems to be , "it's for cooling". Wouldn't not having the gaskets there also help cool the Hybrid too? Was it OEM std to have them on the Hybrid to just keep dirt out?


The Hybrid does have a gap that allows for the heat escaping...

Reading this thread caused me to check🤔...
After a long drive one can definitely feel the heat escaping from this area not covered by the rubber gasket material.

Kind of surprised no one mentioned that one would expect, in the winter time after a long drive this area would show signs of the heat escaping.



there is a water drainage area right in the break of the rubber seal...
 
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