Urvan Z24 getting hot again??

[richURVAN]

Hey folks,

 

Been away for a while and just getting back into my Urvan with the Z24 engine . . . 

 

So it's had a long history of overheating issues which I eventually (or so I thought) solved with a re-cored rad, new water pump, thermostat, head gasket (yes went that far!) and a new 14' electric thermo fan set-up.

 

Haven't really driven it much since then but when I did it stayed under halfway on the temp gauge. Then the other day I was struggling up a hill a bit and noticed the gauge climbing past the mid-way point . . . so I pulled over and the electric fan had stopped working. On further investigation turns out the fan's motor has given up, was brand new 'hi-tec' 14' slim-line fan, curved blades, 1310 cfm from Mishimoto. Any ideas what might have caused the motor to give up? I assume it can handle heat being designed to fix directly to the vehicles radiator? 

 

Anyhow I've written to them and hopefully they can post me a replacement motor. But I'm now wondering what else i can do to keep this motor cool, bigger thicker rad, oil cooler, twin thermo fans, cut more vents in the bumper/bonnet? Any ideas welcome.

 

Ta,

Rich 

[IZRL]

What temperature was it running at when the fan was working? Are you using the vehicle's OEM dumby gauge or do you have an aftermarket one with temp readings? I would fix the fan, get an after market gauge if you don't already have one and get an accurate reading on what temp it's running at. Fixing the fan might be good enough. OEM Thermostat is rated to open at 180° so it should hover "around" that temp.

 

I purchased one of these for both my daily and my 720. Glowshift water temp gauge. Two years in my daily and still good. Bit too modern looking for my taste but it's been good to me so I bought one for the 720.

 

 

 

 

 

Edited April 4 by IZRL

[richURVAN]

Just running off the OEM dumby gauge buddy . . . . your right though I should install an aftermarket gauge and set the auto fan more accurately. I just adjusted it so it comes on just over halfway. Where did you fit the temp sensor for the gauge? Probably also wise to buy one with an alarm.

 

I'm just thinking now whether I've got enough coverage with the single 14 inch fan and perhaps two 10 inch might be better and also increase the CFM . . . but I'm only just researching it properly now. 

 

 

[IZRL]

I ended up buying a joint adapter that goes on the radiator hose. Goes on the top hose. I was looking into getting an adapter that goes from 1/8 npt to whatever the thread on the engine is. To put the sensor where the original one is. But from the research i did. Some folks weren't getting accurate temps because of something to do with the adapter length, or something like that. Long story short. I had already used the adapter on my daily and it worked fine.  I didn't want to deal with the pain of finding an adapter and trying to figure out if it was going to work or not.

 

I used this "Dewhel" water temp joint pipe adapter that has 1/8 NPT thread for the sensor that comes with glowshift gauge. I ordered the 34mm one but it fit a little small for my very old & very stretched out radiator hose. It should fit snug on a new radiator hose i think? So measure the inside diameter of the hose before you order it, if you decide to go this route.

https://www.amazon.com/gp/product/B018FY0Z84/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

 

 

 

     

 

 

 

Edited April 4 by IZRL

[datzenmike]

My fan sensor is on the lower return hose. My reasoning is the top one my spike over 185 or 190F on occasion and turn the fan on but the rad hasn't had a chance to try cooling it yet, and the fan might not need to have come on.

 

 

Something to think about...

 

Where does the warm radiator air from the fan go? Can it easily get out of the enclosed engine compartment?

 

Anything blocking it? Can you makes it easier?

 

Is there any spaces around the radiator for frontal air to get around it and not have to go through it?

 

Can an 'air dam' be put under the radiator that would assist in making a low pressure area behind the radiator?

 

My 710 has a 'belly pan' under the front of the engine to keep road spray off the alternator and fan. Not sure if it would keep hot air from getting out if on your van, if it has one. Perhaps a 'chin spoiler' on the front to force a low pressure area under the van to draw hot air out of the engine compartment?

 

 

TIP:

In an emergency turn you heater and fan on high. This is basically a mini radiator and can lower the temperature reading to get you up that hill. It's not a fix but it works.

 

 

[Stoffregen Motorsports]

When I purchase an electric fan, I go by motor size. SPAL has the most durable fans (in my opinion) based on their massive motor size. CFM ratings are not always accurate either, but if the fan you installed did the job, then no need to go with a bigger fan. I'd definitely look for one with a better motor though.

 

A few years ago I needed some advice on fans. I didn't know what info to believe, so I picked up the phone and called Be-Cool. The tech guy there was more than happy to answer my questions and his knowledge of his industry was bar-none. I spent an hour on the phone with him discussing fan motors, blade shapes, fan shrouds, etc. If you want/need advice, pick up the phone and give them a call. Oh, and Be-Cool uses SPAL fans in their products.

 

Aside from the fan is the controller, which is just as important. Most fan relay systems are whimpy and won't stand up to constant running of the fan. Again, I use a Be-Cool relay system that handles 30 amps continuous. It's comparable to a Hella headlight relay, which is an industry standard term for a big ass relay.

 

Here's the Be-Cool relay and harness - https://www.becool.com/product/fan-relay-harness-excluding-thermo-switch-be-cool-radiator

 

Hella relay - https://www.summitracing.com/parts/hla-007794301

[IZRL]

4 hours ago, datzenmike said:

My fan sensor is on the lower return hose. My reasoning is the top one my spike over 185 or 190F on occasion and turn the fan on but the rad hasn't had a chance to try cooling it yet, and the fan might not need to have come on.

The sensor on the top hose pictured in that post is my water temperature gauge sensor. It's not a fan sensor.

[datzenmike]

Ahhhhh....

 

It's not going to read anything until the thermostat opens, then it will jump down up down till the engine temperature stabilizes.

 

 

The sensor for my lower radiator hose is from a Nissan Sentra SX with the SR20 FWD. That's where it was located. I think the fan sensor comes on at 190 195F??? Normally runs at half gauge goes to about 2/3 before the fan comes on.

[richURVAN]

9 hours ago, datzenmike said:

My fan sensor is on the lower return hose. My reasoning is the top one my spike over 185 or 190F on occasion and turn the fan on but the rad hasn't had a chance to try cooling it yet, and the fan might not need to have come on.

 

 

Something to think about...

 

Where does the warm radiator air from the fan go? Can it easily get out of the enclosed engine compartment?

 

Anything blocking it? Can you makes it easier?

 

Is there any spaces around the radiator for frontal air to get around it and not have to go through it?

 

Can an 'air dam' be put under the radiator that would assist in making a low pressure area behind the radiator?

 

My 710 has a 'belly pan' under the front of the engine to keep road spray off the alternator and fan. Not sure if it would keep hot air from getting out if on your van, if it has one. Perhaps a 'chin spoiler' on the front to force a low pressure area under the van to draw hot air out of the engine compartment?

 

 

TIP:

In an emergency turn you heater and fan on high. This is basically a mini radiator and can lower the temperature reading to get you up that hill. It's not a fix but it works.

 

 

 

Thanks for the ideas Mike . . . I'm no aircraft/airflow engineer but I'll have a look, I think an 'air dam' could be effective, and maybe the older E23's even had one come to think of it. Or they def had a chin spoiler just behind the front bumper. 

 

I waited till the evening to drive home in cooler temps and ran the heater all the way plus left the 'bonnet' (passenger seat) up, it was a loud ride home!

[richURVAN]

6 hours ago, Stoffregen Motorsports said:

When I purchase an electric fan, I go by motor size. SPAL has the most durable fans (in my opinion) based on their massive motor size. CFM ratings are not always accurate either, but if the fan you installed did the job, then no need to go with a bigger fan. I'd definitely look for one with a better motor though.

 

A few years ago I needed some advice on fans. I didn't know what info to believe, so I picked up the phone and called Be-Cool. The tech guy there was more than happy to answer my questions and his knowledge of his industry was bar-none. I spent an hour on the phone with him discussing fan motors, blade shapes, fan shrouds, etc. If you want/need advice, pick up the phone and give them a call. Oh, and Be-Cool uses SPAL fans in their products.

 

Aside from the fan is the controller, which is just as important. Most fan relay systems are whimpy and won't stand up to constant running of the fan. Again, I use a Be-Cool relay system that handles 30 amps continuous. It's comparable to a Hella headlight relay, which is an industry standard term for a big ass relay.

 

Here's the Be-Cool relay and harness - https://www.becool.com/product/fan-relay-harness-excluding-thermo-switch-be-cool-radiator

 

Hella relay - https://www.summitracing.com/parts/hla-007794301

 

Thanks mate.

 

I have this; https://www.mishimoto.com/adjustable-fan-controller-kit.html#key-descriptions similar set-up I think, can run 1-2 fans drawing combined total of less than 25 amps. 

 

Perhaps I had it set too low since I adjusted it based on the OEM gauge, and maybe it was kicking in before the thermostat opened even, so I overworked the fan motor (but I don't think so not that silly - could also just be a defective unit).  

 

They are going to replace it under their Warranty but I've already started looking at SPAL units just they're darn expensive here in Aus. 

 

But I'm confused as to what indicates the thermo fan motor size? How many amps it draws?

 

Which leads me to my predicament which set-up to go for, same as before single 14 inch fan drawing around 8 amps (1350 cfm), the 'bigger' 14' Spal unit I'm looking at draws 20 amps (1840 cfm), or two smaller 10 inch fans drawing 6 amps each (700 cfm). 

 

The twin 10' fans less powerful but covering more area on the rad. I think I'll Be-Cool's equivalent in Oz. 

[richURVAN]

3 hours ago, datzenmike said:

Ahhhhh....

 

It's not going to read anything until the thermostat opens, then it will jump down up down till the engine temperature stabilizes.

 

 

The sensor for my lower radiator hose is from a Nissan Sentra SX with the SR20 FWD. That's where it was located. I think the fan sensor comes on at 190 195F??? Normally runs at half gauge goes to about 2/3 before the fan comes on.

 

I'm confused now where to put my sensors . . . currently my fan sensor is on the thermostat housing, virtually same place as the stock temp sensor. 

 

If I add an aftermarket temp sensor gauge to get a more accurate reading perhaps I swap it with my fan sensor and relocate that to bottom rad hose or it won't make much difference. 

[richURVAN]

I'm also concerned if I did any damage when the temp gauge climbed to 3/4 now and what I should check before throwing more money at this 

[datzenmike]

No damage. Anywhere in that run ranges is ok. It's to show you that something is wrong when it suddenly goes above where it normally runs.

 

Again, here they were known for running hot and over heating and sometimes catching fire. Nissan offered to buy back all that were sold and destroyed them. Owners that kept them really liked them. I had a '63 Ford Econoline van and it was a mid engine also. Always wondered how the air got in and out. 

[richURVAN]

 

plenty of room around the rad and for air to escape i think

 

other pic shows position of fan sensor (two green dots) and oem sensor (one dot) . . . 

[richURVAN]

NOW I think I might of discovered the real problem, the fan just being a subsequent/knock-on effect/disguise . . . 

 

There is coolant (and thus air) seeping in/out of a tiny tiny hole/crack where the rad has been previously repaired. I had the rad refurbished/re-cored when I originally renovated the whole cooling system and that part of the repair has obviously not held up under use. Could that tiny air leak compromise the pressurised system making the pump/coolant flow inadequate? 

 

Also this metal pipe which leads to the overflow has a slight kink, could this cause a blockage/back-up the system? 

 

[datzenmike]

A pin hole would only affect this if the coolant level dropped dangerously.

 

Kink like that is no worry. The over flow would usually (if at all) happen after you shut off the hot engine. The internal heat would cause the engine to 'overheat' briefly and it might be enough to exceed the radiator cap rating of 13 PSI. The expelled coolant is caught in a coolant recovery bottle.  When the engine cools down and contracts, the expelled coolant siphons back into the radiator. 

[richURVAN]

2 hours ago, datzenmike said:

A pin hole would only affect this if the coolant level dropped dangerously.

 

Kink like that is no worry. The over flow would usually (if at all) happen after you shut off the hot engine. The internal heat would cause the engine to 'overheat' briefly and it might be enough to exceed the radiator cap rating of 13 PSI. The expelled coolant is caught in a coolant recovery bottle.  When the engine cools down and contracts, the expelled coolant siphons back into the radiator. 

Then I'm stumped as to why it started to overheat . . . someone pointed this out on another forum . . . 

 

"If you were moving at the time, at least 10 mph, teh fan should not have been a factor.

Check your overflow tank. It should be at the Full Hot level while running. Then when you shut it off and let it cool, it should draw coolant from the tank to the engine.
If the coolant level stays the same, you likely have an air leak in that circuit. It will suck air before it will suck coolant because it is easier. Could be a bad cap, cracked hose, or a hose not going all the way to the bottom of the tank, internally.


If that is the case, you will end up with air in the system instead of 100% coolant. When air gets to the water pump, it will cavitate and not pump much at all."

 

I just had another look under the engine and also noticed tiny bit of coolant on the thread of the fan sensor and also the thermostat gasket is wet to touch so there are a few very minor coolant leaks . . . 

 

But if it's not the leaks that caused that rise in temp? Or matey's got the wrong end of the stick, but it does make me think isn't your fan only for when idling in traffic? 

[richURVAN]

I also found these 'loose ends' while under there . . . 

 

One plastic sleeve connector which looks like it belongs to a sender unit and a metal capacitor which has broken off from somewhere . . . my guess anyway. 

 

I was actually looking for the oil sender unit but couldn't see it. 

 

[IZRL]

The oil sender unit is right below the intake manifold on the block. You could shine a light down from the top of the manifold and see it through one of the open spaces on the manifold right between the carburetor and the head. There's a couple videos that show how to remove the sender from the top under the hood. But i found it easier to remove the front passenger tire, remove the plastic fender shield. and remove it that way.

 

Edit: Just realized you don't have that engine in a 720. So not sure if you have access to the side of the block like i do.

Edited April 5 by IZRL

[IZRL]

Oil sending unit is right below the PCV Valve under the carburetor/intake manifold on the block.

 

 

 

Edited April 5 by IZRL

[richURVAN]

3 hours ago, IZRL said:

Oil sending unit is right below the PCV Valve under the carburetor/intake manifold on the block.

 

 

 

 

nice thanks buddy I'll take another look . . . have you also fitted an Oil Pressure gauge? 

 

I'm keen to see if a) my switch/sender unit is actually there and hasn't just been blanked off by previous owner b) it actually works and my light would come on in the event of low oil pressure

 

But I assume I can't run an electric oil pressure gauge off that sender/wire to light cos it's just a switch?

 

 

Edited April 5 by richURVAN
add more info

[Stoffregen Motorsports]

There's a basic rule that if you got it hot enough that the engine stopped running, that's bad. If it got hot and did not run out of coolant, and the engine did not quit running, then you're probably fine.

 

I have used those adjustable fan controllers before and burned them out, but if you're under the rated amps, again, you should be fine.

 

Motor size is motor size. The SPAL motors are giant compared to others. Be-cool used to have a spec chart on their website, or maybe it was on the SPAL site. It showed physical dimensions of each motor.

[fiveoneO]

Mishimoto is definitely on the cheaper side of things. If they give you a free replacement fan, I'd go ahead and use it, but if not, I'd look into a different brand. You could also try adding some Water Wetter. Its an additive you add to your coolant. I've used it in the past and it definitely lowered my coolant temps.

[datzenmike]

The sender for the oil pressure is between the starter and oil filter about half way up. 

 

Before replacing radiator make sure yours is working at optimum.

 

Lower the coolant level and look at the tops of the vertical tubes. Are they crusty with water scale deposits? If yes, drain coolant and put rad cap on. Lay face down and fill with CLR it's a rust and scale remover, and leave over night. 

 

Check the lower rad hose by looking at it while revving the engine. If the hose has gone soft (they rot out from the inside) see if it collapses from the pump section.

 

Spin the clutch fan with fingers. It should firmly resist spinning and stop as soon as you let go. It should not keep spinning at all. Or are you electric fan now? or both??

 

 

[richURVAN]

14 hours ago, datzenmike said:

The sender for the oil pressure is between the starter and oil filter about half way up. 

 

Before replacing radiator make sure yours is working at optimum.

 

Lower the coolant level and look at the tops of the vertical tubes. Are they crusty with water scale deposits? If yes, drain coolant and put rad cap on. Lay face down and fill with CLR it's a rust and scale remover, and leave over night. 

 

Check the lower rad hose by looking at it while revving the engine. If the hose has gone soft (they rot out from the inside) see if it collapses from the pump section.

 

Spin the clutch fan with fingers. It should firmly resist spinning and stop as soon as you let go. It should not keep spinning at all. Or are you electric fan now? or both??

 

 

Ha two fans now theres an idea! I went electric the old clutch fan was shite and too noisy with the engine right under the seat . . . 

 

Thanks mate I've been through all these cooling system checks / diagnostics . . . I've flushed this system soo many times I've lost count it's clean as a whistle. Plus the rad has been professionally refurbished. 

 

The guys over at InfamousNissan are pretty sure it's the pin hole leak in the rad that's causing the issue, plus it's leaking a tiny amount of coolant from the thermo housing and fan sensor. So it's not a pressurised system. 

 

I'm gonna give those a tighten up and slap some JB weld on this pin hole leak in the rad and fill her back-up with my new fan (when it arrives) and water temp gauge and see how we go. 

 

I'll upload some pics tomorrow got some trick vintage looking gauges.

 

But my god I found the oil pressure sender there is no way I'll be able to access that with a spanner, its surrounded by hoses. That side of the engine on these Urvan's is way too congested. 

 

I'm also going to design with sheet metal a chin spoiler / air dam behind the front bumper to send more air directly at the rad. 

 

Edited April 6 by richURVAN