Radiator Over Heating

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Radiator Over Heating

Unread post by NovoNAvara » January 11th, 2016, 9:25 am

Hi guys. Matt here!. Long time reader. Love coming here for a good read but unfortunately i have been in a bit of hot water (literally). Will keep it short and simple. My partner owns a D22 2004 Navara owned it for a few years and its looked after pretty well. Recently moved in together in Newcastle (2hours north of sydney) and we have been doing a few trips to and from to see family.

Yesterday we returned home and i seen the temp was high and seen that the over flow had filled and pushed out the top and leaked out of the lid. This isn't the first time though, i recently had the thermostat replaced. Because one of the hoses was cool while the other was hot. (Makes sense i think). Yesterday i checked the hoses again and this time both felt about the same temperature wise, so i checked out some other areas.

Now i noticed that the heater never worked. For reasons that is wasn't that hard to put a jumper on befor work and make a hot coffee, i never asked and i realised that the 2 pipes going in to the cab were cut and the pipes were bypassed using hose. This hose is rather short and is extremely kinked because of the bend.(pics included)

Does anyone think this could be a reason that the radiator is not pumping smoothly there for getting to hot?

I have included pics of the heater pipes being bypassed

If anyone could offer there opinions or advice there is 6 beers in my fridge and 5 of them have your name on it!

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Peter Aawen
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Re: Radiator Over Heating

Unread post by Peter Aawen » January 11th, 2016, 10:19 am

The kinked water hoses to/from the heater feed won't be your current issue... All they do is by-pass the heater completely, probably because that was leaking into the foot well!! But that does smack of a lack of on-going cooling system maintenance - regular maintenance& cooling system servicing usually catches that sort of thing before your heater core or taps etc start leaking. :( It'd still be a good idea to get the heater fixed.

Your current problems could be a few things - the least expensive being just that you've trapped some air in the guts of the cooling system when you changed the thermostat & you need to 'burp' that out (otherwise known as bleeding your cooling system - basically just raising the front of the car & then running it at fast idle for 30 mins or so (or at least until the thermostat's been open for a good 5 mins) with the rad cap off & not just the overflow bottle while making sure the coolant level is kept up) - worth trying that; & watch the bubbles that appear in the filler neck - big bubbles, no troubles... they are just the air expanding & getting blown out; small bubbles that are almost foam.... possibly a blown head or gasket! While you are getting ready to do that burp thing, it won't hurt to undo all the covers & shrouds on the rad, clean out any debris, & check for leaks etc, even blow med pressure air or water thru the rad fins to clean out any mud etc; blocked airflow thru the rad could be the culprit, so it's worth doing that at least every few months of 4wheeling regardless! And while you are doing the burp thing, watch to see what the viscous hub or elec thermostat fan is doing - the fan should come on for a short moment or two when you first start the car, then just idle along not sucking much air thru the rad or blowing it over the engine until the engine starts to warm up. If you don't see/hear/feel the air flow increase markedly once the temp starts to rise above the thermostat opening temp, there's a good chance your fan/fan hub is not working properly & needs repair/rejuvenate/replacement - some of the Nissan viscous hub units are serviceable, so you might be able to fix that by cleaning it out & adding new silicone fluid - tell us if you think that's your problem.

If all that hasn't fixed your overheating, then next on the list to look at would probably be either a dodgy rad cap &/or a dud thermostat - yeah, I know you said you'd changed the thermostat recently, but did you fit a quality unit with the right temp range?? Lotsa a/mkt thermostats just don't do the job! Regardless, get a good quality rad cap replacement with the right pressure spec for your vehicle & see if that makes a difference. If your thermostat wasn't OE or good quality OE spec replacement, I'd get a good one & do it again, or at least take the one in there now out & test it to make sure it's ok.

If you still have overheating problems after all that, you should look at returning your cooling system &'the shrouds etc around the engine bay to std condition, just to ensure that you are getting air-flow thru the rad & around the engine bay the way it was designed to work, you'd be surprised at the number of overheating issues that are caused by things like improperly fitting the bonnet, torn rubber skirts that no longer keep airflow running thru the engine bay rather than bleeding it out around the edges, or even just a busted radiator shroud that's no longer sealing on the rad & forcing the air to flow thru the rad instead of letting it out & around it!! But sadly, if it's not any of that stuff above, it's becoming more likely that you've got a head or gasket issue, or maybe an overfuelling issue on a diesel motor.... I can't see enough in the pics to recognise if it's diesel or petrol, but winding the fuel up just the smallest fraction too much on a diesel/turbo diesel can cause overfuelling & high exhaust gas temps which can mean that even the best & most efficient cooling system in top condition simply doesn't have a chance to keep the engine cool!! That usually rears it's head more when you are squeezing the loud pedal to try and stay in 5th gear/overdrive & still maintain highway speeds on long climbs, under load, or pushing into a head wind, but it can also occur at other times just due to heat soak or the length of time you've kept your foot down!! :(

Anyhow, there's a fair bit of reading & a few things to look at - no guarantees it'll solve your issues, but you'd wanna hope it's a good start! ;)

Good Luck! Oh, & welcome to the Forum. :thumb:
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

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Re: Radiator Over Heating

Unread post by hoyks » January 11th, 2016, 10:30 am

If the heater was disconnected/bypassed, it could be for a number of reasons depending on what mods were bolted on, but it could be because the heater core had a leak, so it you reconnect it keep an eye out for a leak. You will probably smell it first anyway.
If you don't want the heater, then I'd probably go with a longer hose. That will let it more of a curve than a tight bend and the water will continue to flow. It will probably make no difference as when the heater control valve is closed there will be no flow anyway.

A new thermostat is a good start.

What is the radiator like? If it gets clogged with mud and gunk it won't let the air through and will run hot. You can try cleaning it (i soaked mine in the kids pool for a day and then washed it clean.... made no difference), but it may be up for replacement.

Is it getting hot when driving at speed, or when driving slowly? The fan hub (that aluminium thing with all the fins in the middle) is filled with a silicone fluid that gets thicker when it gets hot. If the fan clutch is on the way out then the fan won't spin as fast as it should and it won't pull air through the radiator. Try spinning the fan when the engine is cool, then take it for a drive to warm up the motor. Straight after shutdown give the fan a spin again. It should feel significantly stiffer.

When were the heater hoses replaced? When they get old, soft and the water pump is sucking hard at high revs the hose can suck and collapse, so you get next to no flow.

Water pump, if you have the radiator out it probably wouldn't hurt to put in a new one. The bearing and seals will fail before pump stops pushing water around, but it is a pain to get to and is probably due for a new one if it has been in there since new.

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Re: Radiator Over Heating

Unread post by NovoNAvara » January 11th, 2016, 2:18 pm

Thanks Peter Aawen & hoyks

Kinked hose wasnt a problem, was warm on both sides so it was still flowing, (Will deffently fix that though)

Drove it for 30 minuets today temp stayed normal got to friends place and he checked it out, couldn't quite put his finger on it so i suggested bleeding the rad, drove it up the ramp a bit and put about 300mls of water in with the engine running Out come large bubbles followed by small foam bubbles and it never went away even after 25minuets it was still kinda foaming, im no mechenic but i knew that air was comming from somewhere

So i have reason to believe that its got a cracked gasket, booked in to 4x4 mechanic for a TeeKay test and possably a compression test

not looking good,

what kind of figures could i be looking at for a head gasket or a major problem to fix? better let the boss know im avalible for Over Time :(

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