Overheating While On Higway!

[THRLLR]

Hi guys,

i have an issue at the moment with my brothers Nissan. I changed his water pump and thermostat with genuine Nissan items and did his fanbelts. Pressure tested his radiator and that seemed to have no leaks. i thoroughly flushed his cooling system at least 4 or 5 times since changing those items. i got the engine to operating temp and then dumped the coolant from radiator drain plug. waited til engined cooled and topped up with coolant. got engine back to operating temp and repeated process.

Now the issues is that while in traffic (even standstill peak hour) the temp doesnt go over halfway. Once out on the open road doing 100km/h it seems the engine temperature keeps climbing up to 2/3rds or 3/4s and he has to pull over. What could be the issue?

The coolant reservoir is cold and has coolant in it, he turned the heater on max heat and that seems to have kept the temp down so he can drive home but i want to know what issues there could be?

[scotty nm35]

If the cooling system is bled properly with no airlocks and there are no leaks, it may point to lean running. I wouldn't go by the stock temp gauge though.

When running lean on the freeway the pistons get very hot, oil is used to cool the underside of the piston which then runs through the oil to water cooler. This can place extra strain on the cooling system.

The other issue will probably be the radiator, the tubes block up after a while and require replacement of the radiator or professional cleaning, with the tanks removed/replaced. I would be looking at this first.

[THRLLR]

Thanks for that. How do you personally bleed your cooling systems?

Also how do I tell if its running lean?

I have consult and ecu talk running. Stock Temp gauge says halfway but ecutalk says 95deg c. Could it simply be the sensor that is throwing incorrect values?

[Carbon 34]

Thanks for that. How do you personally bleed your cooling systems?

Also how do I tell if its running lean?

I have consult and ecu talk running. Stock Temp gauge says halfway but ecutalk says 95deg c. Could it simply be the sensor that is throwing incorrect values?

Fan clutch is stuffed if no air locks , good coolant with proper amount, no blockages in grill or fins

Turn on the heater is it hot? To flush it needs to be set on hot or it will airlock the head

See if the fan engine off has a tiny bit of résistance when you spin it it should not freespin more then a quarter turn even hot

If it wont spin then its seized and needs replaced

Normally that sounds like a jet and power falls off trying to drag the fan faster

if the clutch freespins its not locking up when needed and results in overheating on road in traffic its prob spinning fast enough to cool and load is lighter

Common problems on rb

Check your oil !!

Edited November 11, 2012 by Carbon 34

[blk94r33]

Won're be a fan/clutch problem or the overheating would be the other way round. Nearly guarantee a blocked radiator.

[MrStabby]

Won're be a fan/clutch problem or the overheating would be the other way round. Nearly guarantee a blocked radiator.

Agreed. Fan does nothing on the highway.

[mad082]

Thanks for that. How do you personally bleed your cooling systems?

Also how do I tell if its running lean?

I have consult and ecu talk running. Stock Temp gauge says halfway but ecutalk says 95deg c. Could it simply be the sensor that is throwing incorrect values?

the stock temp gauge is designed to sit in the middle of the gauge from about 75 degrees up to about 100 degrees, and then it will skyrocket above that temp. this is to stop people panicking when the temp gauge moves to a bit hotter when going up a bit of a hill, etc.

as for bleeding the cooling system, remove the radiator cap, cut the base of a coke bottle and jam it in the radiator filler with some water/coolant in it (so it acts like a funnel) and turn the heater on and start the car. just in front of the intake plenum is a little round metal object with 2 thin hoses and a 10mm bolt on the top, as well as a warning about not opening when hot. this is the bleed screw. so remove this bolt. you should start to get some water coming out of this hole. when it is a solid stream then bolt the bolt back in and you're done.

but there is a good chance that the radiator is your issue if it's overheating on the highway.

[THRLLR]

Update;

That makes sense abouy the stock gauge. Most ppl would panic. Lol

The temp went to 99deg C via consult cable yet the gauge was still at halfway.

Anyway I decided to flush all the coolant out.

Stuck hose into radiator and kept it topped up. Disconnected return hose and let engine run. It seemed that the thermostat opened up as normal and then water started spewing out of return hose as expected. Engine maintained steady 80 to 84deg while doing this. I kept this up until water flowed clear as possible.

I emptied radiator and then filled it with coolant. And got engine but to operating but even though temp went past 90deg the radiator showed no signs of draining water into engine. Steam seemed to make its way out of return hose but the coolant still stayed in radiator.

All I can think of is blocked up radiator (but why did it let water through the engine from the running hose but then not the coolant?) And faulty thermostat, but that is brand new from Nissan.

Now I need to find a radiator for his car.

Edited November 11, 2012 by THRLLR

[blind_elk]

Now I need to find a radiator for his car.

No you don't.

Take the radiator to Natrad or other radiator service joint. They should be able to clean the cores, or provide you with a new core.

[MrStabby]

The radiator can have many of the tubes blocked, so water still flows through but its not cooled effectively. Some radiator shops will pull the end tanks off and push rods through the tubes to clear them out. Justjap have decent radiators for around $300 new.

[mad082]

there are plenty of cheap aluminium radiators on the net. they will do the job just fine. you can have the radiator professionally cleaned (as said above), but the cost of doing this is often not far off the cost of a cheap radiator. worth giving your local radiator place a call to ask them how much to clean it.

as for the water coming out with the hose but not with just the engine running, that could be a water pump issue, (even though you said you put a new pump in). or a thermostat issue. or just the tank being blocked so much that the pump can't flow enough water by itself

[cobbadan]

My radiator had a section about the size of a basket ball right in the middle that was completely blocked. water would still flow freely through the radiator, it would just run around the outside. It was overheating at highway speeds the same as yours.

A way to test it is to take the radiator out, put the cap on and lay it down on its side with the inlet and outlet facing up. boil the kettle and poor the hot water into it untill its full. Then take your hand and feel for cold spots.

[THRLLR]

Thanks for all the advice its awesome. I'll be pulling the radiator out again and I'll do the "cold patch" test mentioned above just to make sure the radiator is truly blocked. While I'm at it I may as well pull out the pump and thermostat and make sure they are fine.

I'll call natrad and see what they charge for a clean. Probably right though., a replacement won't be much more than a replacement.

[gotRICE?]

Im another for the blocked radiator. Everything you describe is pointing at it blatantly.

Mine had a single core NA radiator in it, and did allright with 300kw on the track (two hot laps is all it would give me) and i saw 107 at the hottest. Temp gauge still sitting on half.

Threw in a big aluminium bugger and never looked back. So cheap and so easy.

[THRLLR]

Thanks for the info guys,

I have bought another radiator now and am going to slap it in this weekend and then taking the car for a highway cruise and we shall see, but im 99% confident this issue is about to be fixed!!

Edited November 15, 2012 by THRLLR

[dkbcleaner]

this was happeining to me in the gtt as well. I ended up putting a new justjap radiator for $300 and problem solved. Track days no problem

[Samyr34]

Hey guys same issue with my r34 gtt running 300kw. Other day overheated on freeway. Cooled down in traffic but still would slowly rise. Done a full coolant flush and replaced thermostat plus coolant temp sensor just above top hose. Went to bleed system with x2 bleed screws. Rear one bleed through but front one didn't, plus heater doesn't work when was hot. Any ideas?