Overheating issues!

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My eg's been slightly overheating this summer. I dont drive it to often but when i have temps rise up. The problem is, ive done alot in the past to prevent overheating issues. I recently rebuilt my head, got a new turbo and tune and now its overheating. I dont know its its just coincidence because its summer but take today for example it's 38 outside and the car temp rises upto 84 whilst driving and stays there for a 10-15minutes and then after that it will go upto 95 max and go up and down in the 90's. I've got a aftermarket Koyo radiator, Mugen thermostat (6 months old), anti freeze anti boil coolant, and Thermo fan ive set to power on accessory power so its always running, but the car still wants to go over 90 degree's in this summer heat. Winter the car never goes over 85 degree's unless i thrash it.

Engines done about 75,000 now (b16a2 japspec) and been rebuilt 3 times...currently only has less than 1000 on the engine since rebuild.

Question is the only other things i can think of is either my radiator sitting behind my mammoth front mount isnt allowing enough air through or my water pump is having issues or where my air intake sits its getting alot of heat from the turbo manifold and sucking that hot air into the car air intake temps can get upto 60 degree's.

1 weird thing is the temp only rizes up when im on the freeway over 100. Stop start driving on 60-80km/h roads the temp only gets upto 89 max but soon as i hit the freeway and sit on 100+ the temps sore over into the 90's and slowly creep up to 95. I would have thought, more air flow = cooler but it seems that because the car is under mild load constantly it doesnt like it, which got me thinking it was water pump or air intake temps instead of an issue with the flow to the radiator.

Any idea's?

[rotary_snail]

The fan running constantly may be causing an obstruction to airflow at higher speeds. Thermo fan shouldn't always be running, it's a half assed way to set it up. Get a proper thermoswitch and do it right.

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The fan running constantly may be causing an obstruction to airflow at higher speeds. Thermo fan shouldn't always be running, it's a half assed way to set it up. Get a proper thermoswitch and do it right.

How would it be an obstruction to airflow at higher speeds? Its helping the air, if it were to turn off at higher speeds dont you think stationary wouldnt be as good for airflowing through?

[rotary_snail]

Have heard of the same issue before, not sure if it's the problem your having but it sounds plausible. Basically, your fan spins and causes and obstruction to flow, imagine it as basically a solid object behind the radiator once it's moving at speed(the car not the fan). When it's turnt off the airflow will find it's way around the stationary fan.

This is why all factory fans only run once the coolant reaches a certain temperature, that goes for both clutch and electric fans. Give it a try, disconnect your fan and take it for a drive on the freeway(make sure it's a freeway, and you don't get stuck in traffic). If your problem disappears, then you've found the problem. If it's the same, then you have another issue, which could be your front mount as you suggested.

I would put money against it being a waterpump issue. Haven't had a honda waterpump out yet, but i'm assuming(the mother of all f' ups) that it's a metal impeller. That means, until it basically seizes, it should work fine. So unless it's seized, which you would know, or theres a massive coolant leak from the tell tale hole(another assumption that honda has them), then your waterpump would be working fine.

I'm having an issue with overheating at the moment too and i know how frustrating it can be.

[mooshie]

how close is your manifold to the radiator? you could be getting a lot of heat off the manifold while under boost, heat shield will solve this although it is an unlikely cause.

In all probability it is just airflow. you have an aftermarket front bar and then an intercooler placed in the way of the radiator, the cooler will help to push airflow away from the radiator especially if there are gaps around and behind it. get some corflute (the plastic stuff that looks like cardboard) sheets and duct the air so that once it enters your front end the only way for it to go is through the radiator. Use zip ties whatever to hold it and experiment to see if this solves the issue.

I have the same problem but havent got around to playing like this. I commonly see temps into the mid to high 90's as well. kind of figure that as long as it doesnt go over 100 it should be right. At the moment my water cooling is all standard plus I have an oil cooler in place. The oil cooler dropped temps on the oil by about 30-40 deg f on my gauge, but had little to no effect on water, I though that it might help slightly due to the water/oil heat transfer fitting on the back of the B18C block. Currently I am putting in a Fluidyne aluminium rad which has nearly double the capacity of the standard one.