Heat issues (again)

Serfma

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Mishimoto 3 row radiator or w/e.

Did a pressure test on the coolant system and found my o rings on the crossover tube going into the head was leaking very slightly. Replaced, tested, fixed. Also found a hose clamp that needed tightened just a bit more. Went up to 15-16psi and no more leaks.

Got a hand pump, cigar, and did a smoke test of the intake and found the silver cap on top of the IAC is leaking air and I am about 90% sure it isn't supposed to leak.
1633311646729.png

Will epoxy the top to keep it from leaking unless someone has a better idea.

TPS sensor is leaking air. Well, specifically around the bearing around the TPS shaft or whatever you'll call it. It's very slight but present. Didn't find anything else but I'm going to re-test after I fix the two leaks.

Tomorrow I'm going to drive around to see how fuel trims come up and how temps go, as I've vacuum filled the coolant as well.
 

Serfma

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Fix the leak and re bleed the system them.
Fixed all the leaks, vacuum filled the system after draining it, sitting in a parking lot overheating at idle with coolant coming out the cap. Lol. Driving all of 20 minutes.
 

shurur

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Is that old fan working and is it running at both speeds? I think there were some mk fans that were single speed.

The 96-04 fans move a decent amount of air and are two speed.

You have no AC to make it go into the higher speed, but there should be a way to trip it somehow.
 
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DSG2003Mach1

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Is that old fan working and is it running at both speeds? I think there were some mk fans that were single speed.

The 96-04 fans move a decent amount of air and are two speed.

You have no AC to make it go into the higher speed, but there should be a way to trip it somehow.

the fan wouldnt explain the running warm on the highway.

I run a single speed mark 8 fan, I made a harness for it to keep it plug and play - the factory high and low legs are tied together so when either leg gets power the fan is on. There should be a low and high speed fan turn on signal from the CCRM, just need to verify the fan turn on temps in the tune and make sure the can keeps going. IE low speed 180 it kicks then high speed is 190 it should still be on over 190
 

shurur

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the fan wouldnt explain the running warm on the highway.

I run a single speed mark 8 fan, I made a harness for it to keep it plug and play - the factory high and low legs are tied together so when either leg gets power the fan is on. There should be a low and high speed fan turn on signal from the CCRM, just need to verify the fan turn on temps in the tune and make sure the can keeps going. IE low speed 180 it kicks then high speed is 190 it should still be on over 190
I am wondering whether the fan is running at all or intermittently...or whether the high speed wire is going anywhere.

Hate it to be a worse problem.
 
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Serfma

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An update: I brought it to my work and vacuum filled it in the lot (lol) doing two vacuum pulls and fills, filling the coolant hose up with coolant this time because last time we didn't and I realized after the fact that I injected the air in the hose into the system which likely lead to the overheating.

After test driving the temps are much better. 208, 212 tops during a small pull but it fell back down. I still don't like that it sits around 208. My fan is consistently on. Tied low and high speed in. It is the single speed mark 8 fan. I'm going to GoPro record just to 100% verify.

Long term trims are about 5% higher on driver bank still. Still upwards of 10-20% on both banks. Never going higher than 25% on the driver bank. So could it be hot from running lean? I have Long Tubes which I know lean things out.
 

Serfma

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Idle my temps always seem to drop to 200 - 202 now and sit there. It will eventually drop back down and has gotten a high of 215 in stop and go traffic around town. Pretty confident I have every single leak plugged now.

I'm tempted at throwing a high flow water pump to see if it resolves the issue. Really do not know what else it could be at this point, especially seeing that the motor is in healthy shape from the compression test. Not running excessively lean, have an AFR gauge and at idle I'm within 5%-ish of 14.64AFR. Wondering if I should get a high flow pump, or a smaller water pump pulley? Really stumped as to what to do.
 

shurur

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Idle my temps always seem to drop to 200 - 202 now and sit there. It will eventually drop back down and has gotten a high of 215 in stop and go traffic around town. Pretty confident I have every single leak plugged now.

I'm tempted at throwing a high flow water pump to see if it resolves the issue. Really do not know what else it could be at this point, especially seeing that the motor is in healthy shape from the compression test. Not running excessively lean, have an AFR gauge and at idle I'm within 5%-ish of 14.64AFR. Wondering if I should get a high flow pump, or a smaller water pump pulley? Really stumped as to what to do.
The stewart pump is a nice water pump.
It should help when I go UDP.

I dropped one on when I put a mach 1 lower intake on my unrecalled 99.
 

Roots-type

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There's nothing special about a stock pump. The parts store one you have should suffice, provided it's not leaking. I can only see a high flowing pump being a band aid if there is infact an issue. But maybe a band aid is good enough? Maybe switching to another pump is easy/ economical enough that's its worth trying? That's up to you to decide.

I would get an oil analysis to be 100% there's not a tiny head gasket leak that starts once the engine is hot. If that shows up negative, you may have a block that's been bored out too far or too many times by previous owners and the cylinder walls are too thin. Only things I can think of that are left... granted, 215* is not really that hot in the scope of thing, but it is hotter than it ought to be with a 180 tstat and fan settings adjusted to make good use of it.
 

Serfma

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There's nothing special about a stock pump. The parts store one you have should suffice, provided it's not leaking. I can only see a high flowing pump being a band aid if there is infact an issue. But maybe a band aid is good enough? Maybe switching to another pump is easy/ economical enough that's its worth trying? That's up to you to decide.

I would get an oil analysis to be 100% there's not a tiny head gasket leak that starts once the engine is hot. If that shows up negative, you may have a block that's been bored out too far or too many times by previous owners and the cylinder walls are too thin. Only things I can think of that are left... granted, 215* is not really that hot in the scope of thing, but it is hotter than it ought to be with a 180 tstat and fan settings adjusted to make good use of it.

As far as I'm aware, I don't think the block has been bored at all, think it's been stock it's whole life. Now of course I can't verify it until I tear down again, so that won't be for a long while. Lol.

For sure, 215 isn't hot it's just a thorn in my side and a worry. I've yet to try driving out of town in 4th/5th gear to see what temps raise to if they do. All of my leaks have been sealed as far as I can find.

For a head gasket leak that starts once the engine is hot -- if it isn't present in the coolant or oil, what issues would come up? I personally (with my limited knowledge so far lol) wouldn't think it would cause an hotter-than-normal condition but then again I am here to learn lol
 

Roots-type

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You can get test strips you dip in the coolant reservoir that will tell you if combustion gases have gotten into the coolant system from a head gasket leak. How accurate they are, I couldn't tell you, I've never used them. An oil analysis from blackstone, which can identify even the most trace amounts of coolant in the oil, I can tell you is extremely accurate/sensitive and is why I recommended it. It was also less than $20 when I did one.
 

Serfma

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I'll try an oil analysis and see what comes of it.

At idle I seem to eventually drop to 200F (haven't checked if fan is running or not) but driving is where it'll reach 215F but I'm going to weld a piece of sheet metal in place of the plastic lower air dam to see if it helps. My lower core support is crumpled and bent from it's previous lifetime before me, so I don't have one.
 

DSG2003Mach1

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As far as I'm aware, I don't think the block has been bored at all, think it's been stock it's whole life. Now of course I can't verify it until I tear down again, so that won't be for a long while. Lol.

For sure, 215 isn't hot it's just a thorn in my side and a worry. I've yet to try driving out of town in 4th/5th gear to see what temps raise to if they do. All of my leaks have been sealed as far as I can find.

For a head gasket leak that starts once the engine is hot -- if it isn't present in the coolant or oil, what issues would come up? I personally (with my limited knowledge so far lol) wouldn't think it would cause an hotter-than-normal condition but then again I am here to learn lol
the head gasket on my lightning was leaking between the head and the block, it would get an air bubble and temp would sky rocket (like instantly) and once it cleared would fall down almost as fast
I'll try an oil analysis and see what comes of it.

At idle I seem to eventually drop to 200F (haven't checked if fan is running or not) but driving is where it'll reach 215F but I'm going to weld a piece of sheet metal in place of the plastic lower air dam to see if it helps. My lower core support is crumpled and bent from it's previous lifetime before me, so I don't have one.
that lower air damn is supposed to make a big difference. Normally the bumper opening through the radiator is pretty well sealed with some trim pieces to the condenser and that right up against the radiator. I hadn’t considered it before but the whole thing probably needs boxing in.

I thought I’d seen some people using some kind of plastic curbing from the lowes/hd lawn and garden section to make a taller air dam.
 

shurur

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the head gasket on my lightning was leaking between the head and the block, it would get an air bubble and temp would sky rocket (like instantly) and once it cleared would fall down almost as fast

that lower air damn is supposed to make a big difference. Normally the bumper opening through the radiator is pretty well sealed with some trim pieces to the condenser and that right up against the radiator. I hadn’t considered it before but the whole thing probably needs boxing in.

I thought I’d seen some people using some kind of plastic curbing from the lowes/hd lawn and garden section to make a taller air dam.
Yes there are threads about the air damming. They may be in autocross or roadracing threads. But might be in corner carvers or corral.

I can go through my word docs and look for them. They are pretty old threads. None of them have any decent pics.
 
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Serfma

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Yes there are threads about the air damming. They may be in autocross or roadracing threads. But might be in corner carvers or corral.

I can go through my word docs and look for them. They are pretty old threads. None of them have any decent pics.

If you can find anything let me know. I added a lower piece to help but it hasn't really changed much of anything in the way of temps.

Currently trying to figure out why at WOT it's breaking up really badly, unsure if fuel pump bad or alternator/battery. Battery voltage will drop to the low 12's during a pull around 5k RPM. Always had a longstanding issue where my battery gauge will flick slightly back and forth when turning signal is on, or when I go into first with my lights on I'll see them brighten for a slight moment. Learned the alternator is grounded through the casing and the only two bottom mounting bolts are the ground points.

No idea what's going on lol
 

Serfma

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You guys aren't going to believe this.

I am quite confident I found my heating issue. Yesterday I found out I have underdrive pullies. I would have never guessed because I didn't know what OEM Cobra crank + water pump pulleys looked like until I seen my brother in law's lincoln mark 8 and thought "what the hell they're different?". It requires a crows foot to remove my alt which I always found odd but nothing else besides "thanks engineers".

Doing the math if I replace my crank + water pulley I will see a 47% increase in RPMs.
Current pulleysTarget pulleys
Crank pulley size
6​
Crank pulley size
6.7​
Water pulley size
6.75​
Water pulley size
5.125​
RPM
1000​
RPM
1000​
B calc RPM
888.8888889​
B calc RPM
1307.31707​
Increase from current to target
47%​

Will be slightly off as my current crank pulley size may be off a little bit. Just changing the water pump pulley will net me a 32% increase which I have today, crank pulley will be ordered.
 

DSG2003Mach1

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You guys aren't going to believe this.

I am quite confident I found my heating issue. Yesterday I found out I have underdrive pullies. I would have never guessed because I didn't know what OEM Cobra crank + water pump pulleys looked like until I seen my brother in law's lincoln mark 8 and thought "what the hell they're different?". It requires a crows foot to remove my alt which I always found odd but nothing else besides "thanks engineers".

Doing the math if I replace my crank + water pulley I will see a 47% increase in RPMs.
Current pulleysTarget pulleys
Crank pulley size
6​
Crank pulley size
6.7​
Water pulley size
6.75​
Water pulley size
5.125​
RPM
1000​
RPM
1000​
B calc RPM
888.8888889​
B calc RPM
1307.31707​
Increase from current to target
47%​

Will be slightly off as my current crank pulley size may be off a little bit. Just changing the water pump pulley will net me a 32% increase which I have today, crank pulley will be ordered.
It’ll be interesting to see if that resolved the issue but sounds promising
 

9397SVTs

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Whether the pullies help or not, seems reasonable that they will, you might want to address the coolant itself. I would not go beyond a 50/50 mix and if your location allows, I'd even go to a 70/30 (water/anti-freeze). To assist with lubrication/ corrosion and additional performance, add a bottle of Red Line WaterWetter.

9k=(30).jpg


I have been using it in my cars for many, many years now. Even with 70/30 mixtures, I've never had a problem with pump failures or corrosion in the cooling system.

I also flush the cooling system every couple of years, which probably helps the most.
 

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