XR4ti running cool

I have an '88 XR4ti.

Then engine runs cool. An aftermarket gauge in the factory location reads ~160F while in motion. When stopped, it will creep up to the fan turn on point.

This weekend, I found an XR @ Pick-n-Pull and snagged the purple ring sender from it, a coolant reservoir that is in better shape, and I purchased a new thermostate (192F)

I swapped in the new thermostat (and was saddened when I found the original was still functional), sensor, and coolant reservoir.

The car still runs cold. At a stop on the way into work this morning it reached almost 1/2 up the gauge, but while driving ~50mph it was sitting about 1/4 of the way up. This seem to correspond to what I saw on the after market gauge.

The passaged in the manifold were cleaned out when I did the headgasket about ~10k miles ago.

Also, corresponding with the low temperature readings, heat from the heater is only warm. After sitting still it will get quite a bit warmer as the temperature approaches ~190F, but as soon as I start moving again it is only warm.

Last night I also flushed out the heater core.

What am I missing? Is it low flow to the sender in conjunction with a scaley/slimey heater core?

Thanks, Matthew

Ug. It's been a while since I went through this. WARNING I could be recalling dead wrong.

I feel like I read somewhere that the auto parts store listing for the XR's thermostat is wrong and you need some other part number. I tried to confirm this on google and couldn't find it. I couldn't find a mention on the Merkur Encyclopedia either, so maybe I'm all wet.

(edit)Hummmmmmm. Or was it the radiator cap? Now that I think about it...

Sorry, that's all I've got. Wish I could remember better- I know I fixed this same problem.

In reply to fast_eddie_72:

Yea, it's almost as if there's a pretty gross leak in the cooling system even with a working thermostat. Very odd. Wish I could help more, but maybe that will jog some ideas.

Is the gauge correct?

pilotbraden wrote: Is the gauge correct?

Both the stock sender/gauge and aftermarket sender/gauge show low temp. Along with only warm air out of the vents when heat is on (it does get warming while sitting - corresponding with the gauges)

http://forum.merkurclub.com/forum/viewtopic.php?t=19103

http://forum.merkurclub.com/forum/viewtopic.php?t=19212

I had the Merkur when I moved to Colorado. The day it got here I remember asking on a fourm "what is the 'ICE' light on the center display? Did the block freeze or something?" I was told it meant that I didn't live in California anymore. lol

I had no heat that first winter. I put a heater core in the car, which it needed and was the easiest heater core replacement ever, but still had no heat. It was this same problem, the engine just never got warm. The more I think about it, the more I think I put a t stat in and that didn't fix it, so I tried the pressure cap and that did. But I know there was some issue with one of those being listed wrong and I had to buy it twice.

I know I also ended up replacing every coolant line in that car. It was a pig of a job. I know I did that after I got the heat working though.

Where is that "car I loved but would never buy again" thread?

Apparently, coolant is by passing the thermostat for some reason. On some Fords there is a gasket/O ring that goes around the thermostat to seal it.

The new t-stat came with a big rubber seal. I don't see how it is getting bypassed. (but obviously something is up)

As I suggested on another post. Cover half of the radiator with a piece of cardboard. works great. Everyone forgets that the heater core is a small radiator.

bwkrupp @ MerkurSport wrote: Do you have heat at idle? Only like 2 people believe me lol, but hose that T's off of the thermostat bypass and goes to the reservoir tank needs a restrictor. If the hose is ever replaced, it won't be right. I installed an adjustable valve and tightened it till there was only a drip instead of a stream and instant moar heat. Reason: too little restriction and the water follows path of least resistance, ie it goes into the reservoir instead of to the heater core.

This fixed my heater issue. I'll replace the new FailSafe thermostat with a new Motorcraft thermostat and see if I can get the car up to temperature while moving now.

my SVO ran hot all the time, never less than halfway up the gauge, sometimes a little more. in the winter i wondered how my dash vents had not melted.

/useless input.

EVERY XR4Ti I have owned have run ICE COLD in the winter. I suggest replacing the giant cast iron lump under the hood with a 5.3L Chevrolet engine and a six speed. Even if it still runs cold you would care so much less after the swap.

John Brown wrote: EVERY XR4Ti I have owned have run ICE COLD in the winter. I suggest replacing the giant cast iron lump under the hood with a 5.3L Chevrolet engine and a six speed. Even if it still runs cold you would care so much less after the swap.

Ship one to me and I'll do it.