peeps who know more than I do (I.e. most of you)

"HammerheadFistpunch" (hammerheadfistpunch) 06/04/2018 at 22:33 • Filed to: halp

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What do you think of this plot

It’s my coolant logged from Torque pro on my evening drive home. Looks like my coolant flush and new parts didn’t help solve the problem. From the looks of it I see 2 possible reasons the chart looks like this:

1. air buble

2. Insufficient radiator capacity

The curve shows me that the T-stat is opening properly, and the high idle cooldown suggests that its not a lack of water flow. To me I see it like this:

Engine warms up internally at the right rate, heating curve slows and levels at the right rate with a thermostat opening, once a certain level of heat is reached the radiator simply can’t reject it fast enough and it snowballs.

It will run perfectly on this curve every time, It could be 110 out and it would heat up to 186, sit level there or maybe go to 190 for about 10 minutes, then climb. This was on a 95 degree day at 5000 feet on mostly level roads with light load.

I reached out to the radiator manufacture (CSF) to see if they will warranty their unit but I have low hopes for that. coolant is fresh 50/50, hoses are good, clutch fan kicking on properly and heats up at high speeds (with load) where the high airflow should solve any fan issues anyway...I mean at 80 mph the fan should only be a small part of the airflow equation. Any thoughts?

HammerheadFistpunch > HammerheadFistpunch 06/04/2018 at 22:41

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p.s. I have low confidence in the air buble theory as I’ve burped this sucker at least a dozen times. I see no indication that there is air trapped anywhere. No leaks I can see, I need to pressure test.

HondoyotaE38: A Japanese and German Collab...wait a minute > HammerheadFistpunch 06/04/2018 at 22:50

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Me and u rn:

Highlander-Datsuns are Forever > HammerheadFistpunch 06/04/2018 at 22:55

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Head gaskets are good I’m assuming? Otherwise I find it unlikely that a one year old radiator is bad unless defective somehow. My old datsuns would get hot but on the highway they would cool down with air going through the radiator. Sitting in traffic was the worst and the Z would get really hot.

sony1492 > HammerheadFistpunch 06/04/2018 at 22:55

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What parts did you replace recently?

benjrblant > HammerheadFistpunch 06/04/2018 at 23:11

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208 peak isn’t worrisome, imo.

HammerheadFistpunch > benjrblant 06/04/2018 at 23:13

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It’s worrisome because these are dawdling home temps. I don’t think I’d make it up a canyon pass without spiking to well over 220

HammerheadFistpunch > sony1492 06/04/2018 at 23:13

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Water pump and t stat. Plus a complete cooling system flush.

HammerheadFistpunch > Highlander-Datsuns are Forever 06/04/2018 at 23:15

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Hg shows no signs of failure. Was replaced 60k ago. If it was hot in traffic and cool on the road id be okay... Fan clutch mod and call it good... That it’s worse on the highway than in traffic worries me.

benjrblant > HammerheadFistpunch 06/04/2018 at 23:19

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What does vcexpedition think?

nermal > HammerheadFistpunch 06/04/2018 at 23:23

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Did you check the radiator cap? Are you sure it’s tightened all the way?

HammerheadFistpunch > benjrblant 06/04/2018 at 23:24

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he probably things he’s sick of me asking him about it. When I bought the truck I had the same problems, new radiator and fan clutch solved it then. VERY similar data then to now.

HammerheadFistpunch > nermal 06/04/2018 at 23:24

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si. new cap, fully tight. Tried the old cap too for S&G. same result.

Highlander-Datsuns are Forever > HammerheadFistpunch 06/04/2018 at 23:25

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It is very puzzling I think your comment on the radiator is the most logical conclusion at this point.

The Snowman > HammerheadFistpunch 06/04/2018 at 23:45

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My money is on air in your system.

HammerheadFistpunch > The Snowman 06/04/2018 at 23:46

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it makes sense...but I have no idea where it could be hiding. no leaks, and bled a billion times.

Junkrat aka Rick Sanchez: Fury Road Edition > HammerheadFistpunch 06/04/2018 at 23:50

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I had the same issue with a bad HG on a Subaru(I know, I know). It would be fine around time, but if I took it out in the highway and then idled it would overheat. I had a WRX and STI, so I swapped cooling parts back and forth to try and isolate the problem to no avail. When I changed the timing belt I replaced the HGs and sure enough, bad HG.

HammerheadFistpunch > Junkrat aka Rick Sanchez: Fury Road Edition 06/04/2018 at 23:51

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I don’t see any signs that point to a bad HG. No gas/oil in the coolant, no white smoke etc. when the HG goes on these you tend to know pretty quickly.

sony1492 > HammerheadFistpunch 06/04/2018 at 23:53

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If your radiator cap is bad the coolant mixture will boil at a lower temperature, the correlation is 3°F per psi. Radiator caps can be faulty from the parts store

Motors create more heat under load than at idle so low flow could still be possible.

The radiator may not be able to get rid of the heat because the motor is creating excessive heat from it’s own issues.

HammerheadFistpunch > sony1492 06/04/2018 at 23:55

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I tried the old cap too, same results. I thought about the motor thing, but I honestly don’t think so. I replaced the old OE rad because the tank was leaky and it was cool as a cucumber with the old one and the only thing to change was the rad.

sony1492 > HammerheadFistpunch 06/05/2018 at 00:00

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This new one might have blockages from the factory or something,  a heat gun would tell you.

Dumb question but worth a shot: How hard are your radiator hoses when warmed up?

HammerheadFistpunch > sony1492 06/05/2018 at 00:01

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hard. Also tell me about heat gun testing.

sony1492 > HammerheadFistpunch 06/05/2018 at 00:10

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If they are overly stiff it is a sign of combustion pressure in the coolant system from a bad hg. Head gaskets don’t always fail catastrophically, I know you say they go south when they go on these motors but there are always exceptions to the rules.

Heat gun was the wrong word, I meant infared thermometer/ temperature reader thingamajig.

Temps will be highest from the top of the radiator (highest at the top hose). Lowest temps will be the lower radiator hose, and along the radiator bottom(shock). Heat is not a perfect distribution but if you find vanes of the radiator that are markedly different then their surroundings you know something is up.

HammerheadFistpunch > sony1492 06/05/2018 at 00:15

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ah, gotcha. Yeah hoses are hard but not rocks. I don’t smell any combustion gases in the coolant or on the cap, just smells like coolant.

sony1492 > HammerheadFistpunch 06/05/2018 at 00:37

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Im stumped but heres a thought.

When warmed up the radiator needs to be closed off from the motor momentarily in order to have time to cool the fluid enough. This is why removing a thermostst entirely can lead to overheating. In your graph the thermostat opens but never closes again, the thermostat is not cycling.

Did you bleed the system with the heater turned on full blast?

HammerheadFistpunch > sony1492 06/05/2018 at 00:40

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yup, several times.

4muddyfeet - bare knuckle with an EZ30 > HammerheadFistpunch 06/05/2018 at 02:51

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Is there a shroud for the fan? Removing it can increase airflow through the rad at highway speeds, but normally at expense of low speed cooling

Distraxi's idea of perfection is a Jagroen > HammerheadFistpunch 06/05/2018 at 02:58

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Are you sure your timing and mixture are OK? I used to have terrible overheating in the race car when I had fuel pump problems and it started running lean at WOT with some revs on. Fuel or timing issues might explain why it overheats under load and only when thoroughly warmed up.

HammerheadFistpunch > Distraxi's idea of perfection is a Jagroen 06/05/2018 at 03:10

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trim looks good

if anything it looks like its calling to lean it out slightly.

Rufant > HammerheadFistpunch 06/05/2018 at 05:57

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Did you keep the old rad?

HG or other combustion leak can be tested definitively with something like this.

http://wbtools.com.au/products/automotive-equipment/tee-kay-head-check-combustion-leak-detector/

Stray current corrosion is again something worth checking.

https://www.ipswichradiators.com.au/images/documents/FS119_-_Stray_current_corrosion_in_cooling_systems.pdf

Did you replace/retain the seals from the rad to the body when you fitted the new rad?

If you get your hands on a pressure tester, look for a combustion ‘pulse’ while pressurised and engine running.

Are all the fans working correctly? It looks like the problem is worst when there is a lack of airflow from the vehicle moving, but maybe I’m reading it wrong.

I’m generally thinking the chances of a new radiator being insufficient is unlikely. What’s the timeline for this problem, did the current rad perform ok previously in these conditions or is this the first time it has dealt with the temps?

HammerheadFistpunch > Rufant 06/05/2018 at 11:12

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Sadly, no...I wish I had.

I will see if my parts store rents one this morning

Don’t think its current, its too new a radiator and its rubber isolated with no electric fans.

new seals on the radiator

fans are working properly

previous radiator worked a treat, nothing over 186 ever until the plastic tank started leaking

benjrblant > HammerheadFistpunch 06/05/2018 at 11:19

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Ha, fair enough. I’d be shocked if your new radiator was the culprit. That would be really disappointing.

BLCKSTRM > HammerheadFistpunch 06/05/2018 at 13:30

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I’ve got a couple of thoughts. I have had a similar issue with my M3 (1998, so similar age, and similarly completely revamped).

Factory shrouding is very effective at forcing air through the radiator. When any part of that system breaks, you lose a lot of pressure / air flow through the radiator.

I built some blockoff plates from old election signs (that corrugated plastic stuff), and then sealed the joints with some foam rubber pipe insulation from Home Depot.

Having said that, I still get warmer than I prefer when it’s 100+, especially when I’m going 80+ on the highway. I top out just under 220. I’ve replaced my water pump-mounted fan with an electric unit mounted in the factory shroud, and at rest it can get the car under 190 even in 110+ heat. (the car runs hotter than that- around 200 - in the off season when the AC doesn’t force the fan on).

But I also recognize that the factory needle stays at 12 o’clock from 175-225, and doesn’t get into the red until about 265. So I’m not really that concerned about it. GM Trucks are about the same - 210 is the middle mark, 260 is the HOT mark.

What are the temps for your hot / cool marks from the factory?

Rufant > HammerheadFistpunch 06/05/2018 at 16:44

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Well presuming the supplier doesn’t play ball, I guess you have two options:

A: If you’re certain enough it is the rad, you chuck an OE rad in it and hope that fixes it.

B: You start buying/beg/borrow tools. Infrared thermometer. Combustion gas tester. Pressure tester. Multimeter. Rolled up newspaper, etc. And doing specific diagnosis and start eliminating factors.

Pros and cons both ways. Choice B, you spend all that extra time and money and still end up concluding it is most likely the rad. Choice A, you fit the new rad but the problem comes back at some point because there is another undiagnosed issue.

If I were you , I would probably fit a rad and watch it like a hawk.

Don’t mix coolant brands, but you probably knew that already.

HammerheadFistpunch > Rufant 06/05/2018 at 17:40

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Well I rented (for free!) a coolant pressure testing kit i’ll use tonight when it cools down. I’ll pressurize to 20 psi and look for leaks and check for pulses that ought not to be there. i have an IR therm but its hard to get access for readings so well see