Vannin' Home Forums General Discussion Generic How To ..... Hail Damage...Help, Ideas, Input NEEDED!

Sounds good. I'll check the alternator when I get a chance. I put a new one in right after I bought the van (accidentally as I didn't realize at the time that the regulator was external) and then figured why bother taking it out. Can't remember if I bought reman or new on that one but either way it has been doing work for about five years now.

As it happens, we have had to take an unexpectedly early trip back east. So, from 70's for the high at 9000' to 90+ a 0'. Oh, the joy!

The good news is that I have been able to test out a few things here and there so now I have a few stats and some questions that perhaps you could answer.

1) Day one we drove our usual highway speeds (slow :o) with the screen still intact. She rode at just one bar below the H the whole time. No up, no down. Oil gauge was back to its 'normal' behavior and we had the AC running the whole time on NORM, Low.

2) I wasn't too pleased with where she was riding during that time so for the last leg of our journey we first pulled over in a parking lot and I removed the screen. At idle, still sitting with the AC still going the temp dropped 1/2 a notch.

3) That made me wonder if the screen wasn't so much affecting the wind flow when driving down the road but more not allowing hot air to escape; if that makes sense.

4) Since removing the screen the temp gauge has stayed steady at that same point 3.5 notches up from C with very little fluctuation even when AC is on MAX, High.

5) I finally figured out where I had put my fancy multi-meter and when we arrived at our evening stopping point last night I left the van running with AC still on (because it was awfully HOT in Nebraska) and immediately went to the top and bottom of the radiator. I stuck the tiny probe slightly under the radiator hose and the tank on the top and read 166 deg then in between the bottom hose and the rad and read in the low 140's. That was quite interesting to me. Seemed low for what the gauge was saying all day.

6) So, this morning I ran the best test I could with temps and the temp sender. I held the temp probe on the top part of the sender (just under where the wire connects) while D watched the gauge. We took readings at each mark and a few in between. This is what we got.

A) Upon starting gauge just below C - 71.7 deg
B) Dead on C - 84.9
C) One line above C - 97
D) Two lines above C - 113 *
* At this point I put the temp sensor on the external portion of the exhaust manifold and it read 250'ish
E) Two and a 1/2 lines above C - 131
F) Three lines above C - 140 **
** At this point I put the temp sensor on the block just below the carburetor and it read 120 (a little confusing but confirmed it and it stuck - I may try this one again one day in different places)

We could not get it to go any higher at idle so we started driving and she rose the last 1/2 notch and held steady at 3.5 notches above C. When we pulled over at a rest area I removed the doghouse and measured at the sender as I had been. It measured 166 (which coincided with what I had read at the top hose of the radiator the evening before).

So.... that's the latest. Although I would really like to put the screen back on because cross country travel is a total bug killer, I will most likely leave it off for now and deal with the consequences to the condenser at a later date.

My question... I would really love to know digital temp readings at each notch and some in between if anyone could possibly provide them to me.

If it matters that the engines are the same or not... don't forget mine is the 5.9 360.

Well, time to hit the hay.

Adios for now.

I should also point out...

1) Our gas mileage this trip as been same as it usually is on a hwy trip.

2) It is probably a bit significant temp wise to note that the Stant (non-fail-safe) thermostat that I have in there right now has two tiny holes drilled in it. So, even when it is closed there will be some leak through. I did this at the recommendation of my fav garage mechanic because I kept blowing my fail-safes and he said a Stant non-fail-safe would be a better bet. I was afraid of a non-fail-safe given my experience blowing the others so he suggested the two small holes that would at least give me some 'leak through' instead of all HOT in the event of a problem.

When I was taking readings by My digital multimeter, I has the sensor probe taped tightly to the thermostat housing, with a blob of grease around it to better transfer heat to the thermistor.

I did record temperatures but I cannot locate where I wrote things down at, but as far as a comparison goes, your probe would have to be at the same spot as mine for any comparisons to be valid, and I believe my DMM reads about 5 degrees F cool as I also have an IR temp gun like this:


My gauge was acting funny, because I have a small coolant leak, and there was air trapped in the intake manifold and my radiator cap was not allowing the system to draw from the overflow tank on cool down.

I am using a MotoRad Tstat, which already has a little jiggle valve to allow the air to bleed past it, but for whatever reason It was not purging the bubble.

It took parking uphill and allowing the engine to warm up to hot before it purged the air, and then the gauge returned to the normal range.

If removing the screen did have a noticeable effect, then I will theorize your radiator is partially clogged, and the restricted air movement from the screen was just enough to reduce its efficacy to the point where it is noticeable on your gauge.

When you have the radiator cap off, you can see two rows of tubes about 1/2" to 5/8" wide each on a standard copper brass radiator. Are these tubes obstructed? You can easily see if they are.

Here is my Aluminum radiator which has 1 inch wide tubes. And when I say 'tubes' they are flattened tubes, 1 inch wide about 1/8 inch thick and run from the top tank to the lower tank. The thin fins mate to the tubes.




In that chart I posted above of the gauges and the normal range, mine pretty much rides right in the middle at normal temps. When I replaced the mechanical voltage limiter with the Solid state electronic one, I calibrated it so that the temp gauge needle returned to its normal range. I have not yet determined how near to 5 volts that I have it set as there was trial and error involved until it read as I was used to seeing, and getting the DMM probes on the dashboard cluster contacts is not so simple, and I hate piercing wire insulation just to check.

I say keep the screen off. The AC condenser fins can take a beating, but blowing a head gasket or cracking a head from running too warm for too long is much more expensive and has much higher consequences, even if the engine continues to run mostly fine. The 360 and 318 seem to run so dang smooth even on 7 cylinders it is easy to just keep going..

Check to make sure your lower radiator hose is not collapsing at higher rpms when the engine and radiator are hot.

If your radiator tubes are obstructed, then your transmission is also running hotter than it would like, and heat is the transmission fluid's enemy, and causes it to age faster, which in turn then fries the transmission. So Sniff that tranny fluid and hope it is pink or red and sweet.

I do plan on having a DMM thermocouple Epoxied with thermally conductive epoxy to both T stat housing base, and my alternator, just because I like data.

I bought this longer one so It can reach my DMM which I rest on My doghouse:

http://www.amazon.com/gp/product/B0...t=true&ref_=oh_aui_search_detailpage

68, Not a lot of time this morning as we have to get on the road but a few quick things...

What temperature does your van run at on an average? I know numbers won't be exact based on location and units and weather and such but some indication will at least give me a range. I was surprised that readings both at radiator and sending unit were the same and yet not even hot enough to open our 195 thermostat all the way.

Before we hit the road I opened the radiator to see what was what (fins looked fine and fluid still nice green color) but the noticeable difference from usual was the loud escape of air when I pulled the cap - never had that before. I've pulled it a few times more since hitting the road this time and have not had that sound again so whatever it was, I'm hoping it is out or on its way out. I'll keep the hill trick in mind in case I still think there is some air in there.

Also, I've been keeping an eye on all of the rad tube and no collapsing at all at any temps.

Well, speaking of temps...it's already heating up here at 7:00 a.m. Oh 9000' where did you go?!

Going by memory, with the thermocouple taped to the base of the t stat housing, with a blob of grease around it, 172.5f highway rose to 189F under 25mph after coming off highway, then settle back to 172 range under 25mph around town.

If you pulled off the radiator cap cold and air rushed in, your radiator cap is not allowing it to pull coolant from the overflow tank.

You should see if the level on your coolant overflow tank is dropping, when cold in the morning.

Thanks. I'd think my 166 is pretty close then as it has remained consistently there. She isn't smelling hot, actually seems a bit cooler than usual given that it is 96 deg here. Tranny fluid is still a pretty pink and oil is doing fine considering I was supposed to change it prior to leaving but this was pushed up two months. Will get it changed in a couple of days when I am in a location and temp that permits.

We recharged the AC which has made the trip tolerable but at these temps it is having trouble keeping up.

"If you pulled off the radiator cap cold and air rushed in, your radiator cap is not allowing it to pull coolant from the overflow tank." I'm not sure if it matters but it was more like air rushed 'out'? Not trying to split hairs but that is what it was like, a big release. Checked again this morning and no air release. Also, rad fins look great.

With the heat we are giving her a break every 60 miles or so (which allows her to drop a full notch before we get started again). She's doing really well and I am leaning toward thinking there was air in the lines or the sender or gauge are fluky.

Been monitoring the coolant overflow tank and it appears to be working just fine.

Well, time to cool off indoors for a bit before heading back down the road.

Thanks and I'll keep you updated!

Air rushing out is fine since the cooling system is a pressurized system. You just have to make sure that the radiator cap you are using is designed to be used with a radiator overfill/puke tank. As the engine heats up the coolant expands.

In older cooling systems the expanding fluid was held in place by the radiator cap at normal operating temps, resulting in a pressurized cooling system. Pressurizing the cooling system raises the boiling point of the coolant due to........SCIENCE! If the engine overheated, the coolant could expand past the ability of the radiator cap to seal the system. The hot coolant would then shoot out the side of the radiator cap or, in later designs, out the radiator overflow tube and onto the ground.

In these types of systems it was recommended that the radiator be filled only to the point of the coolant being 2-3 inches below the radiator full neck. This left rom for the coolant to expand and not puke out the tube.

Environmentally friendly types got upset at cars puking radiator fluid on the ground, and engineers decided that it would be more efficient to recover that fluid and cycle it back into the system, so recover tanks were designed. These tank required the use of a different type of radiator cap that would still seal the cooling system but would allow coolant to flow into the overflow tube and then into the overflow tank when the engine got hot but also allow that same coolant to be sucked back into the engine once the motor cooled down.

Your 88 definitely has a recovery tank and should have come from the factory with a correct radiator cap to allow the overflow tank to function. If you or a previous owner has ever replaced the radiator cap you may want to buy a new one and make sure that it is a stock replacement cap made to work with an overflow tank.

It sounds like the thermostat it working, the clutch fan is working, the radiator cap is working, but your system isn't cooling as well as it should. The fact that removing the screen from the front of the radiator made a noticeable change in the temp reading suggests that you have either too small of a radiator or some kind of blockage in the radiator. You may also need to clean out the fins on the outside of the radiator and straighten any bent ones. When was the last time you washed out all the bugs and dirt from the front of the radiator and AC condenser?

Also, what coolant mix are you using? You should be OK if you are using a 50% mix of the old green ethylene glycol and distilled water.

Thanks, Reed.

I put a new 16 psi Murray Temp Control Cap on the Rad when I bought it since the original had a cracked seal. It has worked great and until now the cooling system has worked without incident, as well. I did inspect the cap the other day though just to make sure it was not developing any problems. All still looks good with it. Everything with regard to overflow tank seems to be in order and working. I've been watching that, as well.

The coolant is relatively new (can't recall off of my head just when we put it in but it wasn't long ago that I drained the old and put in a new 50/50 mix or something like that). Again, worked alright until recently and still a pretty green so not thinking anything related to that.

As for whether the thermostat is working right or not... that has become my new focus. Since I am doing an oil change today I will also grab a new thermostat and pop it in. We had a two day layover in GA before continuing on in this heat to FL. So, I figured good time to see if a new thermostat puts things right or not.

The reason I started looking toward the thermostat is that upon watching it with less of a 'fear' of needle rising allowed me to be more patient and calmly observant. What is happening is that it is riding quite well (temperature wise - though maybe a 1/2 - 3/4 notch above where it normally does). The last few times the needle started to rise I was in a position to be able to pull over and let her cool down if I needed to so I watched patiently and it would reach a certain point (higher than usual at one notch below H) hesitate there for about five seconds before going right back down. It was consistent with this and probably has been all along but we were freaking out at the higher reading and kept cooling her off. Anyway, I am starting to wonder if this is the thermostat opening later than usual - sticking a bit or something of that sort.

As for the radiator fins, we put in a new AC system (including condenser when we bought the van). Since the Rad is completely blocked by the condenser that is the only time we have straightened the fins on it. But we did get it all straightened out at that time and cannot see how anything can get in between the two to cause any further problems. The condenser had some hail damage and we are slowly straightening those fins out but it isn't enough to have changed the cooling system efficiency.

We hit the road again tomorrow at high temps and highway so we'll see how it does with the new thermostat.

There is a one wire temp sender for the gauge on the intake manifold. On mine it is on the passenger side of the intake. Make sure the electrical connector is not all oxidized or loose. I remember you had issues with this sender years ago correct? Could not get it out?

If your temp gauge swings quickly when driving down the highway, then the dashboard voltage limiter is not holding a steady voltage or your battery charging voltage is swinging wildly. Your gauge could be failing, or the connectors on the back of your gauge cluster need to be cleaned.

The gauge cluster could also have a weak ground. I ran a redundant one just to be sure, and of course all electrical connectors get cleaned with Caig Deoxit d5 spray.

I resoldered mine the round connector on my gauge cluster. Not that they needed it, but because I had it out and a new Solder gun and am anal retentive when it comes to electrical resistance.

If you have the same firewall pass through as me, for the DMM's thermocouple, I'd recommend keeping it attached to the base of the thermostat housing, and see if it also rises when the gauge rises into the uncomfortable zone.

The dash gauge simply cannot be trusted 100%, so any other data you can collect to corroborate, or negate its readings, is helpful.