Cooling system

[grtskydog]

I've been having cooling issues that I thought I could solve without too much dough or tail-chasing...bless my heart.

The combo- 351W, TorkerII, TFS1 cam, Durspark dizzy + HEI module, 2-row aluminum radiator (Arts Parts), Contour dual fans, FiTech TBI....er....ahem CFI.

First, rewind a few months. I was tuning my FiTech system, which has a little dash-mounted handheld controller. I noticed that my temps were nice and steady at cruise, but with a closer look, I noticed the Contour fans having to come on/off to enable this nice stable temp. I had read in the past about the little air dam (diverter) under the radiator that creates low pressure behind the radiator, but I figured it was for the aero-nosed cars more than the four-eyes with our ample grills. Nevertheless, I went to the Pick-n-Pull and grabbed a Town Car dam...looks almost the same as the Fox, but a tad wider. No dice. Still wouldn't cool at speed without the fans running. Around that same time I noticed a little puddle of coolant under the bellhousing, which I eventually traced to the water pump leaking/weeping (the TC gasket was soaked and the coolant ran in the seam of the oil pan back). Project time. Maybe this is my problem.

I decided while installing a new pump, I'd do timing cover gaskets, and while I was in there I'd slide in a Comp XE274. I've got the nifty little magnets that hold up the lifters so cam swap is a breeze. Burped the system good when I was done and drove it. No dice. Still hot.

Guys, I hate to say it but I think I need a radiator. I've had this one for awhile. I did "garden hose flush" it when I was messing with the water pump, and I didn't see any real nasty buildup just looking in the tanks, but that's really anecdotal. I even used the "comb" on the condenser where it was kinda nappy. Anyway, I'm up for suggestions. This is a pretty solid 400hp engine, and that 2-row has cooled the 351 just fine in the past. I think the Contour fans just pull enough air that it can even make an old radiator cool. What's good out there? I ordered a LMR "SVE" radiator, but it arrived damaged. To their credit, it was a pretty easy refund process (and I got to bash up the radiator). I'm thinking of getting something along those lines...if I can get one to show up shaped like a rectangle.

[deathbypsi]

What is 'hot"? Do you have some actual temp numbers at idle,driving slow, driving fast? What t-stat in it? Where are you picking up temp readings from on motor?

[Ourobos]

My 11.5:1 418w with over 600 N/A HP ran cool on the street with the same fan, an Edelbrock water pump, and a 4 core aluminum radiator.. I had the air diverter if that helps..

[Ourobos]

Also mean to ask what thermostat you have, I'd suggest a 180

[erratic50]

Any under drive or overdrive on the waterpump vs the crankshaft?

If you run an underdrive the 93 Cobra pulley (that I recently posted about) will get you back to 1:1

If you want to overdrive the pump like lots of guys with super chargers do - again that's your pulley

My 1986 GT has had a near stock 5.0 most of the 25 years I've owned it. I had to put a 3 core radiator in it the moment I charged the AC and added some some base timing just to keep it cool in the Midwest summers. Mine had a SD friendly old school 5.0 cam from the 90's and some minor intake porting. It wouldn't stay cool worth crap with a 2 core-- even with a 180 thermostat.

The stock fan pulls some air 100% of the time. I found out by breaking a fan clutch and having to remove the fan to limp home that I was very hard pressed to keep it cool even at highway speeds on a cool day without any fan.

When I put on 2.5" exhaust and 1 5/8" equal shorty headers and x pipe the under hood temps dropped a ton, but it still liked to creep up on the needle on hot days even with a 3 core.

Currently I run a FB-169 radiator and high flow capable 195 degree thermostat. I'm about to switch to the cobra pulley to get the water pump back to 1:1 after adding an underdrive because it's back to running 210+ on hot day with no AC.

[grtskydog]

Sorry...I did leave out some info, didn't I?

Stock pulleys, parts store stock flow pump, 180 t-stat. The fans come on somewhere around 193-195 range. Running down the road, system can't maintain, so fans come on. Last time was 89 degrees with the a/c blasting. That's definitely a factor, but it did still require fans without the a/c on. I don't have an "a/c on" trigger for fans. My next experiment is to program the controller to like 220, then run the car (no a/c) and see what it stabilizes at when moving. Nothing has gotten "hot" yet (ie 230+). The fans haven't allowed it. Theoretically, if the fans can maintain 195 sitting in the driveway, the car moving forward should produce the same result without fans. So much for that theory. Contour fans pull some air! Either that or my air diverter is installed incorrectly (unlikely... it's under the radiator like stock).

Otherwise it needs a better radiator...or I just plan on running higher temps. Next question is, what will those temps be? Won't know till the weekend. I'm traveling now.

Other answers- I have autometer gauges and the sensor is in the stock location...it is dead on. The sensor for the FiTech is a Delco mounted in a EFI style heater tube. It reads a few degrees hotter than actual, but that's ok...I compensate.

[deathbypsi]

Also check the lower hose to see how soft it is. Most have a metal spring inside so they cant get sucked shut. Id say if it never goes over 210 under any condition I wouldnt worry bout it.

My 83 TBird has a Griffen 3 core,supercharged 5.0 and no kind of defector under the core and I have never seen mine go over 200* yet.

[cb84capri]

I ran a stock two row for years without problems, then it started getting hotter, and hotter, and hotter... I got it up to temp and used an infrared temperature gun and found several rows in the radiator had blockages near the middle of the radiator. So I put a Mishimoto in. It was good for a couple years, then similar problems arose again. This time it was the thermostat. It had been in there for quite a few years and wasn't opening as much as it was supposed to. I checked it against the same model replacement in a pot of hot water with a candy thermometer. I like Mr Gasket high flow thermostats, but I always boil them before using them with a candy thermometer to check the opening point since bad ones do get out.

Also when I burp the system I jack the nose of the car up as high as it will go so the rad cap hole is the highest point in the system and run it filled as much as possible with the rad cap off, and add more coolant when the thermostat opens to get all the air out. Good luck with it, hope you get this sorted out.

Cale

[grtskydog]

The spring is in the lower hose, so that's all good. The Tstat is good...I put my hand on the upper hose and it gets hot right around 180 or so. I didn't even think about putting my infrared on the rad...but I'm guessing I'll find blockages. Thanks for the feedback guys.


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[grtskydog]

Looks like it's all good. Driving with a/c on in July heat it runs around 195 (AutoMeter) or 199-203 (FiTech display with NAPA sensor). My experience assures me the AutoMeter is "more correct" so I set the fan control on the FiTech to come on at 204.