Hey after reading every thread in here about overheating I bought an UG to check the temperature. At the same time I noticed that my coolant was "disappearing" after a couple hours of city + highway driving.

UG temp shows average temp of 200F to 212F. Median is around 204F. Too hot, right? So I bought a new thermostat 180F (the grey genuine one), but still needed to know where the coolant leak was coming from.

My oil is not milky at all, so I excluded a head gasket issue.

Changing my belt again yesterday (long story), I noticed some liquid and stains in the bottom lower right corner of the plastic thing that holds the radiator.



Removing that plastic, I found quite a bit of thick liquid on the metal plate beneath it. (Picture below)



It may no be super clear in the picture, but there was quite a lot. I wiped it clean and will check it later in the week. So my best guess is that the radiator is leaking. I checked the hoses and none of them have any visible liquid or stains. They all look actually new. The radiator is from 2014, it's a nissen.

Couple of questions for you lots that have way more experience than me:

- The high temperature could be due to the radiator leaking / malfunctioning, correct?

- The right process that I should follow to fix this
1. Change thermostat
2. Change radiator
3. Fill in with coolant
4. Bleed

Any other steps? Any thing specific to do when the new radiator is installed?

As always, thanks for your help!

 

Those temps are normal and good for a factory thermostat.

Radiators normally leak where the small nipple that goes off to the overflow tank is, the nipple cracks or breaks. Also look where the screw for the plastic shroud on the drivers side goes in right above the top of the radiator. Often sloppy people will put the wrong screw in there that is too long and it will puncture the plastic top of the radiator there.

 

Very often head gasket leaks are external so there's no milky oil. The weak spot in the head gasket is at the rear of either head. That is where a water passage is very near the edge of the gasket, and there is only a very narrow bit of gasket.

I doubt the thick deposits you found in front of the radiator result from a coolant leak. I've never seen coolant thicken like that.

The best thing to do to track down a coolant leak is to get a cooling system pressure testing kit from any of the major auto parts chain stores. They will loan it to you for free. Follow the instructions and pressurize the system as specified. Any leaks should then be revealed.

 

Oh, I read here that anything above the 200F and peaks around 215F are high and should be dealt with... is that not the case? I'll change the t-stat anyways.

I will check this for sure, and report back. Thanks!

 

215 is a touch high, anything under 208 is ideal. At 210 the aux fan kicks on, so it's nice to always keep temps under that. I have a 180 t-stat, and my temps are 195 (absolute lowest, going fast downhill), to 204-206 (idle).

 

The thick liquid is more at the back of the radiator. But not sure where it coms from. It just under the radiator, hence why I thought it was linked to it.

Ok, good advice. i'll find store this weekend.

 

What I meant to say regarding those temps being normal is that that is the range the factory intended. Of course many agree on not liking running so hot so we buy the grey 180 OEM stat. I'm getting 185 on fast downhills and 195-197 at idle.

 

180 grey - 188 ish driving in light traffic or hiway speeds up to 197 at idle as low as 183 on long downhills.

Prior to that with an unknown greenish white thermostat as per the OP 197ish on the move, 212-15 at long stops idling.

 

Ok super clear guys. I'll do the test other weekend to see where the leak is coming from and post pics here to get your advice. I'm kind of hoping for the radiator and not the head gasket to be honest....

 

so did a pressure test, and the radiator is leaking. bottom driver side. All the rest is as far as I could see "leakless"... I also found a small leak with the pan leak. Damn, this thing is non stop.

Anyways, so ordering from LK8 a new rad. I'm fairly clear on how to change the T-Stat.

For the radiator, as I have secondary air injection, is there anything specific that I should watch out for?

Overall, I'm thinking the following - any adds or watch outs are welcomed.
1. Change thermostat
2. Change radiator
3. Fill in with coolant
4. Bleed

Thanks