Bullbar causes overheating?

[dieselfan]

Was at Toyota other day, they had a Hilux with a bullbar, I asked what brand they said ONCA as they disliked ARB / TJM. Their op, ONCA was lighter, stronger and sorted out overheating issues they suspected. Truth?

[Kagiso II]

Oompie was thinking [again] - The design of the "bull bars" [replacement bumpers] are such that it pushes air downwards, which air will flow underneath the car - now THAT will be cause for concern.
All the other things like extra spot lights - the air that 'hits' it cannot disintegrate or "go away' or vanish - it will just flow past the said object [light or whatever] THUS - the same amount of air will still get to the radiator
By which I mean to say, that in my view, if the "bumper" design does not deflect air completely away - that the fitment of a "HD bumper will have no adverse effect on the vehicle's cooling ability.
Fan baled design & condition of the viscous fan clutch .. now THAT is another matter.
- is what oompie thinks...

[OB1]

Definately some truth. I have a valid test and control.

My Defender has a Madman that takes coolant temp readings digitally. Very accurate. Done in the bleeding hole at the thermostat housing.

My previous bullbar that was essentially steel pipes running from left to right, and two upright supports holding it together. taxi got in my way. the damage to that Hiace is more than to my vehicle but still. Bullbar had to be replaced.

New one has a winch plate (empty at this point) that obstruct the grille to some extent.

Usually range is about 66-69 depending on speed and incline. on hot days 75 is usual, and towing over 80. I am going to double check everything, going to KNP next week will keep a close eye on coolant temp. But sofar I observe an increase, I did some highway driving on the N14 to Krugersdorp, and the temp climbed upt to 75 with colder ambient temp (night and winter)

[Pieter du Toit]

Pieter,en as ek kan bylas.Die waterpomp pully en ander fan blade wat n baie groot verskil op my 4.2 gemaak het.
Ek wil net noem vir wat dit werd is oor die thread.
The pully and fan made a huge diierance but did not slove the problem.Pieter has the same fan and pully on his engine,and he did all the other that fixed his overheating.Rather it's not overheating it's running hot.
Cheers

Yes true Frans and thanks for reminding me - I totally forgot about the waterpump pulley and other type fan blade that was added as well. And the last part of your statement is also very true - it was running hot rahter than over heating.

Sien Frans die alzheimer's is besig om my te bekruip jong

Hoe lyk dit - gaan ons 2 die Patrol 60 party daar in die middel van die Vrystaat loop bywoon = ons kan vir Hermi ook saam nooi dan maak ons n manne uitstappie daarvan - hopenlik sal dit oor n naweek wees ( as daar n party gaan wees)??

[JG Shields]

Julle kan al die Patrols wat julle in die Kaap bymekaar kan maak sleep met een Patrol. Maak dit 'n patrol trein. Dink net hoe goed sal die gemiddelde brandstof verbruik dan tussen al die Patrols wees.

Ek dink hier's 'n oplossing vir almal wat die Patrol se brandstof verbruik wil verbeter. Koop nog 'n Patrol en sleep die een met die ander. Sodoende sal die gemiddelde brandstof verbruik tussen die twee halveer.

[Kagiso II]

[Sias]

'n Bietjie "off topic", maar ook hitte-verbonde:
Wat sal die invloed op enjin temp en "under bonnet" temps wees as ek my headers laat "ceramic coat"? Sovêr ek weet is keramiek mos 'n baie goeie insoleerder teen hitte, so dit behoort alle temps bietjie af te bring?
Of het ek nou die kat aan die stert beet?

[Peter Connan]

Sias it is supposed to help. This is one of the two reasons why they do the ceramic coatings on manifolds.

I am not sure how much difference it makes though. I once had heat-shielding tape on the exhaust manifold of a Lotus Europa I used to own, and although I never measuered underbonnet temps, it did lower them to the extent that I had slightly less problems with overheating. It needs to be added that in the Europa, the radiator is mounted in the nose but the engine is mounted behind the driver, so it should make more difference in the Patrol.
However the tape caused my manifolds to start cracking. Perhaps with new manifolds (like yours) this won't happen but I am not sure. Also the exhaust behind the manifold will be much hotter, so make sure you have heat shields where the exhaust goes past the rearbox and particularly the clutch slave cylinder (or is yours automatic?).

Just getting back on topic for a moment, if any bullbar can add to overheating in a Patrol, mine should do it because I have expanded-mesh screens covering the whole grill area. However removing them makes no difference, and I have also not been able to notice much difference from fitting or removing a radiator seed net.

[Sias]

Thanks Peter
I'm having a complete new system fitted at TNT in Germiston - from the headers to the tailpiece. Will see on Saturday what it looks like and what effect it has on all temps.

[beast]

This discussion has been verry interesting to follow. My Navara does not have any problems since I fitted the replacement bumper. I am looking for a second hand replacement bumper for my 2004/5 4.8 patrol and was hopeing that somebody might know of one or is going to take theirs off due to the overheating. Let me know. I see some comments about heavy on juice. When we got our Patrol it was verry heavy. I met up with a guy in Pretoria who used to work for Nissan S A and he adjusted the air intake with a hand held computer, and guess what the petrol consumption betterd to the extent that it was verry noticable. He explained, that the dealers computers are connected to the Nissan system and the system has only one setting, most probably a safe setting. He knew the parametors and set the air intake, which made a huge difference. Dealers cannot do this if they dont have hand held system. When we have the 60th we can share some of these stories.