Hey,

Not sure what to do at this point, as I've replaced the entire cooling system with the exception of the Heater core.

So... here's the story. Engine is freshly rebuilt (less than 1200 miles on it), and it kept pinning the temp gauge. So, I figure, no problem - get one of those analog ones. I did. It tells me the car runs at 240 now.

So, to recap: new 180 Stant thermostat, brand new water pump, 3 tube Champion radiator plus all hoses. Heater core was replaced a while ago, but shouldn't be the issue, anyway.

Block was fully cleaned less than 1200 miles ago. Timing is good, and running HEI ignition.

Running 1 9" fan and 1 10" fan. Both electrical, and come on precisely at the right time.

Is this normal? Should I try premium gas? (My rebuilder took some off the deck and some off the head).

Also, don't want to burn out my transmission. Can I do this? (trans is cooled the normal way - at the bottom of the rad)

_________________
63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.

No way is 240 normal and yes your trans will run hotter now.

Do the fans have any effect at all? If they have an effect, then you know there is some coolant flow. The air coming off the fans should be good and hot.

Without some sort of blockage or lack of flow, what comes to mind is the fans don't move enough air.

Does it run hot at idle, or only when driving, if so- how fast? You should get a digital IR pyrometer- Amazon has one from Mastercool for under $50. With that you can get temp readings from various parts of the system. (infrared pyrometers get changing results on different surfaces, shiny metal reads one way, dull metal a 2nd, rubber hose yet a 3rd. The most accurate reading is from a flat-black surface- I sometimes use a spot of black paint or a piece of electric tape-firmly applied) You can move the IR gun across the radiator & "see" hot or cold areas that could indicate a problem.

Try putting the heater on full hot- hi blower when the temp gauge goes up & see if that helps anything. You should get lots of really hot air from the ducts- this would confirm that the engine/ water pump can produce adequate coolant circulation & the system isn't "airbound".

I usually see four "causes" for high engine temps. 1) Poor coolant circulation through the radiator. The top hose & tank get hot but the lower hose is much cooler (50-100* or more cooler). This covers everything from water pump problems, stat, restricted radiator cores, to lower hose that collapses at high RPM (there used to be wire "spring" that went inside the hose to prevent it from getting sucked flat). These shouldn't be issues since most parts are new, but new parts can still be bad.

2) Inadequate airflow thru radiator. Here the lower hose temp is fairly close to the upper (maybe 30* or less). I have seen debris & dirt in the rad fins (or condensor fins on A/C cars), fans that weren't big enough-fans that didn't have full voltage due to wiring/ alternator faults, to fans that were wired backwards & blew air forwards instead of sucking it back. Once I had a defective rad that had the fins poorly bonded to the tubes & just couldn't transfer heat very well. While a 3-tube radiator has more "capacity" & transfer area, unless it is well designed it can actually restrict airflow thru the core & have only minor benefits compared to a good 2-tube unit.

3) Head gasket/ combustion leak. Hot combustion gas will play merry hell if it gets into the cooling system. This can be difficult to pin down with absolute certainty. I use a combo approach: a tool that pressurizes the cooling system so I can inspect for coolant in the cylinders, a chemical test that reacts to combustion gases (CO2) in the system, & a gross leak test (cold engine, seal a funnel to the rad neck & fill halfway with coolant- start the engine then "lean on it" in drive- watch the fluid level for fast increase or lots of bubbles. A BIG leak can spray coolant out like a fountain).

4) Wacky engine faults. This is the catch-all for problems like way-late timing (did you verify that your timing marks are accurate & that your mech & vac advances work?) or restricted exhaust system. Could even be late cam timing- what's your compression results & engine vac at idle?

hope this helps

_________________
63 Valiant Wagon
225 - 4 bbl

The first thing I would do is verify that the thermostat is operating. Put it in a pan of water and heat up the water. Using a candy thermometer note at what temperature the thermostat opens. It is very possible to have a bad thermostat out of the box.

I have another question/suggestion. You indicated the engine was recently rebuilt and the radiator was replaced before the rebuild. Did the over heating exist before the rebuild? Why did you change the radiator? When you changed the radiator did you FULLY flush the system?

My thought and reason for the questions is if you used any of the fix in a can products it may have left deposits in the engine that transferred to the new radiator causing a blockage.

_________________
2006 Jeep Commander
2013 Chrysler 200

1964 Valiant 4 Door
1965 Plymouth Barracuda
1967 Chevy Camaro

Reed: Before testing thermostat for correct opening temperature, make sure it was installed correctly in its housing. Spring side of thermostat has to be facing (in contact with) water jacket of head. If installed backwards engine will over heat, and hoses will look like they want to explode. Also a small hole drilled in thermostat at 12 o’clock will aid in bleeding air after coolant refill.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

True.

See if lower hose is cooler than upper. This indicates blocked flow somewhere. Most common cause is thermostat not opening. Please report progress.

Sam

_________________

Yep, didn't actually do this, but was running the car WITHOUT a thermostat before I replaced the rad (which was this morning). Still 240 then.

Haven't drilled a hole in it, but I'm curious if that's even necessary?

_________________
63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.

I have never drilled a hole in any thermostat I have ever installed in any vehicle and I have never had a problem with air being trapped. Just put the car on ramps or point it uphill once it is fully warmed up and turn the engine off. Any air will naturally go uphill to the radiator.

What temperature are the fans set to come on at? Do the fans turn the right way? Are the fans fighting each other (two pullers or two pushers)? Are the fans blowing the correct way?

You say the block was cleaned out, but what about the head?

1. Actually have an IR thermometer. It's cheaper (a Microtemp MT100). The car runs hot whether idling or highway driving.

2. Fans are on correctly. These are pullers, and they are blowing hot air.

Using my MicroTemp thermometer, I get 118 degrees at the bottom hose, 155 at the top. I also shot it at the Thermometer housing and I get 180. Obviously, I used no black paint for the test - just the natural surfaces.

I put on the heat and fan, and it does blow VERY hot air. (It's hard to tell, as it's about 90 here, but it's definitely making heat)

3. Wow. No idea how to begin with this test. Question: If my coolant was full of exhaust, wouldn't there be other issues? As in, if my head gasket was leaking, wouldn't the engine be having a ton of other difficulties?

4. Timing is spot on. Any more and I'm pinging. I'm about 5 before TDC, maybe a little less. I haven't done compression tests. Obviously, I thought this was just a cooling system issue.

That's what I got for now... Thanks everybody for chipping in. I'm going crazy with this thing!

_________________
63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.

The head was reground and everything, and in fact was from another car (same style, though). One of the reasons why I rebuilt the first engine was that it was crap. Turned out the bottom end was great, but the head was junk!

Fans come on at 180. Two pullers. Wired the same.

_________________
63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.

Well, it sounds to me like either the thermostat is faulty or the radiator is too small or has a blockage in it preventing coolant flow.

What type and what mix of coolant are you using? i.e. 50/50 ethylene glycol water mix, or 60/40% glycol water mix?

What is your total timing at cruise?
and what RPM and speed is that?
Have you turned the radiator upside down to dump/flush the junk out?
Do you have any loose or old hoses letting some air into the system?
Do you have a radiator over flow tank?
Is it working? by drawing water back in the radiator on cool down?
What pound radiator cap are you running?
Have you tried any water wetter?

Sounds like a bad temp sender on the engine or lots of air bubbles....if you able to get those temps with a hand help temp gun.

My set up runs good on 90 degree plus days. The two 10" fans seem to keep up fine as long as I don't go over the mountain pass when it's that hot. I do run a 160 high flow stat in the summer to stay at 180 and use an air dam to shove more air into the radiator. Do you have the fans mounted near the top of the radiator like mine? or in another configuration? I also run an 18 pound radiator cap.

Click on the red link to view pictures.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Total timing? Not sure. It's just after 5 before with the vacuum advance off. I have a Weber 38/38 which does up the timing at idle quite a bit.

No tach installed. Idle is about 850 (with my timing gun)

Radiator is brand new, just out of the box yesterday. I ran the system for a bit with a ladies nylon in the top hose. Took some junk out, albeit not a lot.

Probably the only hose I'm curious about is the small one from the pump to the head. Everything else is clean and new.

Yes. I have an overflow tank. Weirdly it doesn't seem to be doing much.

13 Pound cap.

Haven't tried Water Wetter. I'm running about 50/50, maybe stronger to the distilled water side.

Engine sender is about 2 weeks old. Brand new electrical temp gauge.

_________________
63 Plymouth Valiant V200 Convertible.
225, HEI, Super Six with 38/38 Weber, Electric Fans, Scarebird discs, FirmFeel front swaybar.