Thermostat Gauge not reading properly

TheBro

Okay so I made sure the AC was on and ran it for a good 20 minutes when I filled it back up. Drove it and then checked again to just top it up a little. The radiator cap is 13 psi and I tried to replace the thermostat sensor in the housing a month ago but had purchased the wrong one. I had pulled the original and looked it over and seemed fine, there was a small burn mark on it, however.

There's nothing coming out of the exhaust and I suspect it is my thermostat, I fear I put too much gasket maker onto the housing and it my have clogged the little breather hole for the thermostat. But it seemed to run fine and I drove it over the holidays on a good 7 hr journey and no complaints. The cab did feel a little hot but that's normal for running it for so long, or is it?

Currently looking at replacing every thing but the radiator and the fan at this point.

MazdaMitch

Axel-Breaker-Earl

When you install the thermostat, make sure that the "jiggle pin" on the thermostat is at the 12:00 o'clock position when viewed from the passenger front fender.........or the driver's side if you are right-hand drive over yonder!

Cusser

I jacked up the front right of the B2200 when I installed a thermostat so gravity would help hold it in place while I installed the outlet tube.

kz6fittycent

I just replaced my thermostat with a 192F (it had a 180F) and what a difference. It runs warmer, which is good, because now I actually have heat in the cab. It also runs smoother, which also makes some sense because it's running at the temp that the engineers intended for it to run. Recommended change IMO.

Cusser

kz6fittycent I just replaced my thermostat with a 192F (it had a 180F) and what a difference. It runs warmer, which is good, because now I actually have heat in the cab. It also runs smoother, which also makes some sense because it's running at the temp that the engineers intended for it to run. Recommended change IMO.

I did the same a few years ago, and found the same. Hotter, faster heat was very noticeable.

Many believe hotter engine temperature forces more moisture out of the oil so engine parts last longer in today's engines.

MazdaMitch

I've ran the 180 for years and have great gas mileage, good heat in the winter, and fantastic in the summer especially with AC on.

One time in the summer the metal barb near the thermostat housing for the bypass hose broke off due to corrosion and as I was traveling home I glanced at my gauges just in time I would say because I saw the temp gauge almost to the hot.

I immediately pulled over to examine what was going on and had nothing on me to repair it. So what I had to do was just park it and wait for it to cool and drive it until it got a little too hot and stop again and wait for it to cool and drive it again until I could reach home.

There's a lot of guys that run their trucks hot and what I'm saying here is I attribute me not running hot and destroying my cylinder head to me running the 180 thermostat and having time on my side to notice it because I believe that when it's a 195 or 192 thermostat it runs almost halfway up thus giving you less time to react in the event of a disaster.

Since mine runs a quarter of the way up I feel like it gave me time to react without a damaging the engine.

TheBro

Okay a bit of an update, went to my local auto shop to grab new hoses and a thermostat. While I was driving my clutch was biting a bit when I changed gears, arrived back home and there was a lot of coolant dripping out onto the ground.

I suspect I’ve got a blown head gasket. I’ve taken apart all the hoses and there’s a lot of rust buildup in both and the housings. Should I replace the radiator and water pump?

I’ve never done this work before and I don’t have a garage to work in also this is my only vehicle so looks like I’m going to on the bus for a while.

Any tips when doing this work would be great. Currently watching your head gasket video @MazdaMitch, so I should have good gauge on where to go. Just scared of what I could find

Cheers

Kauri

MazdaMitch

TheBro the clutch grinding is probably a whole separate issue like the slave cylinder going out.

Can you locate where the fluid is coming from?

It's probably rusty because at some point someone used tap water in it instead of a proper mix.

Iay would start with just flushing the radiator with a hose and get out as much rust as possible, and replace your hoses (need to anyways) and fill with premixed super tech Walmart coolant.

Some tidbits about a head gasket.
With the cap off the radiator look for bubbles, this would indicate the head gasket has a leak and allowing exhaust to get into the coolant.

If it steams out the tailpipe, coolebt is leaking into the cylinders and burning off (steam).
OR you may be lucky like in the video and it leak out the side between cylinder head and block.

TheBro

MazdaMitch Firstly, thanks so much for the replies. Love the video content it’s helped a lot with this journey for the truck.

Damn I just replaced that last year, think I’m going to replace both the master and the slave this time around.

I haven’t been able to locate where the leak is coming from but I’m assuming right at the back on the passenger side, there’s a lot of grease build up and was kinda wet when I had a look at the engine but I’m only assuming.

Going to order a gasket kit tomorrow and see how far I can get with it before I head back to work. I think this could work out to be quite expensive as my exhaust manifold is pretty rusted and I fear once I get the heat guard off I won’t be able to put it back on so I may need to get another exhaust system and maybe a new water pump as it could be rusted. Won’t know till I have a look

Secondary question, if I change the engine from a B1600 to a B2000 will I also need to change the gear box? Contemplating just putting a larger engine in at this point.

Cheers, thanks for the help

MazdaMitch

TheBro Damn I just replaced that last year, think I’m going to replace both

Don't forget to replace the two rubber lines one going to the slave and one on the firewall because they become corroded over time deteriorate the interiors of the lines and foul up the master and the slave so replace the master at the slave the two rubber lines in the fluidity should be good for many many years. Go to my YouTube channel and you'll see I did a video on a slave replacement and it discusses the copper crush washer that is necessary that no longer comes with the slave anymore and that helps seal it because a lot of guys will put one on and never get a pedal in this because it's getting air in there because they didn't use a copper crush washer.

MazdaMitch

TheBro Secondary question, if I change the engine from a B1600 to a B2000 will I also need to change the gear box? Contemplating just putting a larger engine in at this point.

I don't know.

I will say this on the passenger side under the intake on the 2000 and the 2200 there is some rubber lines one of your lines could be too old and it could be leaking you really need to clean everything up and investigate because you may not have a head gasket issue at all.

Cusser

TheBro I’m going to replace both the master and the slave this time around

Myself, I always replace these as a pair. I also have replaced both flexible clutch lines on my own B2200.

I also have a copper crush washer assortment kit from Harbor Freight, as needed that when my replacement front brake lines also came without crush washers. Cot savings, you know !!!!

TheBro

MazdaMitch I removed a couple of these hoses. Funnily enough a couple years ago this hose burst on me and it was my first repair.

This is a photo of the bottom pipe, it’s full of rust. The hose I replaced was caked in rust too.

How would I go about cleaning this? Just shoot some water down through it?

Axel-Breaker-Earl

That is the inlet or outlet for your oil cooler. You should be able to flush the oil cooler out with water pressure. Make sure your oil filter is screwed back on to keep the water out of the oil. I would definitely flush the whole cooling system though.

TheBro

Here’s an update!

Ive struggled for time to work on the truck this week, lots going on with mahi but today I took the head off and was able to see the Head Gasket.

Most of the week was spent looking for parts and I’ve found a VRS kit which should include the head gasket, along with a Valve Cover Set. This was a bit daunting as I’ve only watched videos on YouTube on how to do this, but I’ve labelled all the bolts and have been able to start cleaning.

here’s some photos of the head gasket

Pistons are covered in carbon but can see the crosshatching on all the cylinders. Think the next steps are to get the block out and take it apart - going to take to a shop to look over and get a professional on the case.

While that’s there I’ll start to work on cleaning the head and porting the valves. It’s been slow progress without a garage to work out of but getting closer. Need to calm down when looking at parts - money doesn’t grow on trees.

i think the engine is in good nick its been long overdue a clean. I’m unsure if I have a blown head gasket or freeze plugs which was the original reason for this journey but I’ve learnt a lot just doing this so it’s all turned out for the better.

Any advice on how to get a block out without a hoist would be appreciated

MazdaMitch

One time me and a friend drove a good ways to get a block out of a truck and it was sitting in the truck.

So I had to go underneath and disconnect the transmission.
Then we wrapped a chain around the block and use a 4x4 stretched across the fenders just to give you an idea how big it was and we got on each side and squatted and lifted the block out.

Axel-Breaker-Earl

If your cylinders look good, and there is not a noticeable ridge on the top of the cylinders, no deep vertical grooves/scratches in the cylinders, then you can rebuild your engine without boring it out and installing larger pistons. This will save you some decent money! You will need to lightly hone the cylinders (I use a 240 grit flex hone) to get the new rings to seat properly though.

I have rebuilt a dozen or more of these Mazda engines, and most of them I never had them bored out.......the metal in these blocks is very good.......rarely any wear to speak of. I have one I drive every day, and it has nearly 100,000 miles on the engine AFTER I rebuilt it this way! It had 100,000+ miles on it when I rebuilt it also.

kz6fittycent

Hey folks - PSA here:

Make sure you use @MazdaMitch 's Torque Spec page when tightening your thermostat housing, and do NOT go by this spec.

My truck started having wee little accidents when it was warmed up...

Turns out my "calibrated wrist" needs some adjustment.

Cusser

kz6fittycent Make sure you use @MazdaMitch 's Torque Spec page when tightening your thermostat housing, and do NOT go by this spec.

Also: make sure that your thermostat housing is perfectly flat; if not, sand it flat using wet/dry on a sheet of glass.