Heat issues (again)

[Serfma]

'96 Cobra, ever since I've had this car I've had issues with heat. I've only gone as far as swapping head gaskets and doing my best to inspect everything head related. Valves looked good, none bent, cams on driver side looked slightly scored but nothing that stood out to me that said "This is bad!"

I have replaced the following:

Radiator (Mishimoto)
Radiator hoses
Water pump
Fan (Mark 8 fan, not the most CFM moving fan, just the tier down)
Fan IS shrouded and properly mounted against the radiator
I have no condenser. Removed when I got it.
188* thermostat
Coolant burped properly following Ford 4.6L DOHC Coolant Refill & Burp Procedure by Reische Performance Products
Have only long tube headers, everything stock.
EGR deleted, tuned out. (Issue present even prior to deleting EGR)

When I replaced the head gaskets I did not degree the cams. It was at a time that I did not know better. I am trying to narrow down what is going on and where this heat is coming from. I know stock cams / sprockets have enough play to mess with cam timing by up to 6 degrees, can heat be from cam timing? I've thought that my rings are going bad, but I don't know if bad rings can cause excessive heat.

Long term fuel trims at idle sit around 10% passenger bank, 18% or so on driver bank.

Any help will be greatly appreciated.

 

[cobracide]

Can u elaborate on the heat symptoms leading up to the issue.

 

[Roots-type]

What are you using to determine water temp? What is happening when it gets hot? Have you replaced the ect sensor? Is it losing water? Need more info. I strongly doubt cams are the issue though.

 

[Serfma]

Not losing any coolant, I have a quarterhorse to datalog everything if need be.

Water pump was from RockAuto, ACDELCO 252516, More Information for ACDELCO 252516 which now that I look at it I'm starting to wonder if this is the crutch

I am using Torque Pro with an OBD2 scanner (and my QH with Binary Editor) to determine water temps. Coolant temp sensor has been replaced.

An out of town trip I was seeing a max of 220F 4th gear 60 - 65mph, later that night on a drive back I was seeing 230F and started seeing coolant leak out of the very top coolant reservoir hose. Just very slight leak, as in pressure built up too much / too hot and it found a way out. Not really noticed any other symptoms outside of it being a little rough to start if I turn car off and let it sit a few then back on before it has had ample time to cool down.

 

[cobracide]

FYI common mod 175 degree thermostat. AC will boost your temps.

 

[Roots-type]

The pressurized system, as I'm sure you already know, is designed to relieve pressure at the reservoir cap. Because 230 is really not hot enough to push water, and the fact it's leaking from a hose and not the cap like it's designed to, makes me think you've got either a bad clamp, bad hose, or bad/dirty connection. If it were my car, and I was positive the hose and connection are good, my next step would be replacing the clamp and then vacuum filling the system. The burping method technically 'works', but it can take repetition and is really only a last resort for the driveway mechanic. As finicky as these systems are, vacuum filling is the only 'right way' to do it imo.

 

[DSG2003Mach1]

FYI common mod 175 degree thermostat. AC will boost your temps.

Ii dont see a 175 vs 188 making a huge difference. I tried a 170 vs 180 in my mach and all it did was run super cold on the highway. 230 at 65mph seems too high imho.

also says he has no condenser so AC isn't a factor.

Id keep it simple and open the fill on the crossover to check if more air worked around.

do these cars have the 2 temp sensors? is it possible to hook them up backwards or something? I swear I've seen something about that and one reading higher than the other

edit: I agree it doesn't seem right to be leaking from a hose # 230, the cap should go first

 

[Serfma]

They have two temp sensors, one for each head, with the "hotter" driver side head belonging to the dash gauge. The OBD2/ECU temp sensor is on the passenger side of the crossover instead.

As for being possible to hook them up backwards, not possible. Harness won't reach across and two different connectors.

Coolant reservoir cap has been replaced already before, all within the year, year and a half. Only thing I've not touched is the heater core. Tightened up the smaller hose (I think it's the overfill hose, connects radiator to top side of reservoir) and nothing so far.

 

[DSG2003Mach1]

Tightened up the smaller hose (I think it's the overfill hose, connects radiator to top side of reservoir) and nothing so far.

ya that doesn't sound like so much of a problem them, I was picturing like the upper heater hose to the radiator

I don't know if theres a way to test the heater core for a restriction or not, the failure mode I always hear about is it leaking into the passenger compartment.

All I can think off hand is a water flow rate issue.

when it starts running warm does it spike up to that temp and drop sharply back down or it a slow climb up and down.

 

[Serfma]

ya that doesn't sound like so much of a problem them, I was picturing like the upper heater hose to the radiator

I don't know if theres a way to test the heater core for a restriction or not, the failure mode I always hear about is it leaking into the passenger compartment.

All I can think off hand is a water flow rate issue.

when it starts running warm does it spike up to that temp and drop sharply back down or it a slow climb up and down.

I just took a drive out of town and datalogged using torque pro (ass slow to update each sensor I know) and I noticed it was 208F as I was going out on the highway, slowly up to 210, then 212, over the span of around 5 minutes or so. Once I went up a hill, in fourth keeping it 60-65 so extra load it eventually climbed to 215-217, 219 at the tops then slowly came back down after I crest the hill and coasted down. Once I was in the next town over I still had 215 - 217 temps although stop and go traffic (no AC) in 1st through 3rd gear. Not dogging on it at all just normal driving.

Water flow rate is what I am concerned with too. I don't know what stock flow rate vs this acdelco is and I don't want to slap a high flow on it in the off chance that it isn't a flow rate issue and that it's just a bandaid over the real issue.

I don't have any leaks inside the cabin, is there any way to check for leaks without pulling the entire dash? lol

 

[DSG2003Mach1]

i dont think you need to check for leaks from it, just saying i dunno if it could be clogged up internally since the radiator is new.

 

[Serfma]

Yeah I don't know if it could be clogged up or not. I've flushed and burped the system around 5 times since I got the car a year ago or so. I have a vacuum kit that I will try next

Edit: Well if it was clogged wouldn't I get no heat? I get plenty and I mean plenty of heat through my vents lol

 

[shurur]

You say you have a small leak. I would fix that. I had an issue with those spring clamps on the little reservoir hose.

As said above, look to clamp it with a good clamp.

Leaks mean air is getting in the system and temps are going to creep up.

Make sure the temp sensors are tightened.
Ask me why I say that.

Eliminate each logical thing. Anything left..no matter how unbelievable..is it.

Pressure test it.

Then you may need a leakdown test..but don't go there yet.

 

[Serfma]

Just compression tested tonight, leak down will be done tomorrow. Will vacuum fill the coolant as well. I assume I have to drain the coolant from the block on both sides? Or can I use the vacuum tool to pull the coolant out maybe?

Comp test results:
Done at 118F coolant temp, 4 cycles for each cylinder tested, WOT

#1 - 185
#2 - 170
#3 - 175
#4 - 175
#5 - 175
#6 - 180
#7 - 170
#8 - 170

Compared to last year before I did the head gasket lol:
#1 - 180
#2 - 180
#3 - 175
#4 - 190
#5 - 110
#6 - 115
#7 - 110
#8 - 105

 

[Boost or Bust]

Thermostat? Someone correct me if I’m wrong but isn’t the cobra thermostat different then the GT? I thought I read somewhere that the cobra thermostat has larger openings or a different design.

 

[Serfma]

Thermostat? Someone correct me if I’m wrong but isn’t the cobra thermostat different then the GT? I thought I read somewhere that the cobra thermostat has larger openings or a different design.

188*, from what I've seen I have checked diameter of the opening to the ones I've had and they're all the same, none too small but then again I'm not certain.

 

[Serfma]

Since I've compression tested and everything has came out good is it even worth leak down testing since if there were bad rings or valves it'd show in the compression test?

 

[shurur]

I would be pressure testing the coolant system to see whether it holds.

Be forewarned that mine held when cold, but I eventually found my temp sensor was finger tight only.

 

[me32]

How old are the temp sensors?

A leak in the system will cause air in it causing it to over heat.

 

[hotcobra03]

The radiator

Was changed ,,how old is it?

Radiator was my issue when running hot,,

I found during testing ,while sitting at 220 plus air didn't help on radiator. To cool

When I added cold water over it my Temps would fall like a rock ,

Than would cycle with low speed on/off as long as water was flowing over radiator

I did the sve 3 row and been fine since