Truck runs cold

Eric-Smedlund

Hey guys, i was wondering why my truck runs so cold. I just recently fixed my heat but the truck runs so cold that the heat doesn’t work that well. The truck barely gets above the C on the temp gauge. I also just recently replaced my thermostat. With a 180. I think that is the OE temp. The truck is a 87 b2000 but has a 2.2 swap

Any help would be appreciated. Thanks!

Axel-Breaker-Earl

The original temp thermostat was a 192° unit.......not a 180° unit.......I'm pretty sure. BUT, even with a 180° thermostat, you should have some heat. Where do you live, and what are the outside temps getting to there?

Eric-Smedlund

Axel-Breaker-Earl
I live in northwest arkansas, its getting colder here. Gonna be starting to get into the low 30s here soon. The heat in the truck makes it better than none but i would like it to be better. I think ill throw that 192 thermostat in it and see if it runs better and see if the heat works better too. Thank you!

Cusser

A decade or so ago I wasn't satisfied with the heat output on my '88 B2200 Cab Plus; so I replaced it with a 192F/195F Stant thermostat. I'm in Arizona (can get down to 25F though) and I don't run hot in the summer either, AC always on. The B2200 produces hotter and faster heat than either my 1998 or 2004 Frontiers too.

Eric-Smedlund

Cusser
Okay, ill throw that 192 in and see what happens. Thanks for the help!

MazdaMitch

I run a 180 thermostat on all my trucks and it runs about a quarter inch above the C.

I have plenty of heat I have to turn it off in fact and runs plenty cool in the summer even with the AC on and I'm in Mississippi so we have all types of weather from 111 sometimes to 0.

MazdaMitch

Eric-Smedlund please report back and let us know what happened.

Eric-Smedlund

MazdaMitch

will do!

Cusser

When I change a thermostat that's vertical like on the B2200, I jack up the front right side of the truck, helps gravity hold the new thermostat in place as I change it.

Also make sure that your outlet's surface is perfectly flat; if not, sand it perfectly flat on a sheet of glass. My factory outlet had become warped a little.

kz6fittycent

It's currently 30F here in North TX. Just went for a drive and my engine with a 180F thermostat didn't want to keep things warm. It could definitely be starting to fail or get lazy, but I'm going to need to replace it regardless. I'll be switching to a higher temp thermostat.

MazdaMitch

To get through the short cold snaps you can always cover half the radiator with a piece of cardboard.

Axel-Breaker-Earl

Also, make sure that you look at this thread.........

https://mazdaminitruckin.com/forums/d/424-broken-hotcold-blend

and that you are certain that the heater core control valve is opening ALL the way up, so that you are getting plenty of coolant flowing through the heater core.

Red91EFI

Before you mess with your thermostat, make sure your coolant control valve under the dash is open all the way. Just because your dash control knob appears to be all the way hot doesn't mean that valve is open. There's an excellent thread with pics that shows how that works. I don't even use the dash heat control because it's broke, I easily open the valve by hand.

Cusser

After a 10-minute drive, feel the two coolant pipes at the engine firewall, should be hot. If so, then your thermostat is fine and your issue is inside the dash.

All: make sure the cooling system is bled of ALL air; I jack up the front end and take off radiator cap, and run engine for up to 20 minutes, adding 50/50 until it won't take any more.

By the way, I formerly used a 180F thermostat but did not get adequate heat. So a decade ago I changed to a Stant 192F/195F thermostat and get fast, hot heater (better than in both my Nissan Frontiers). And I never run even half-way up on the gauge in Arizona desert, Cab Plus, AC....

In the past, I did use the cardboard block-off trick, think on a 1979 Toyota truck.

kz6fittycent

I can touch my radiator....bare handed. It's the thermostat. Thanks tho - there was an issue with the heater core mechanism. Someone had broken the tab that one of the levers connects to. It's back in place and the heater core is opening, and blowing "warmish" air.

Eric-Smedlund

update, it kind of worked. it seems a little hotter inside the cab but i think my coolant control valve is now the problem. at least for heating up the cab. the temp gauge shows a little above the c but still not as high as it should be. not quite sure what the problem is. I think it could be because I'm using a automatic rad in a manual truck. nonetheless I'm not totally freezing when I'm driving it which is a major plus from when I had zero heat

Eric-Smedlund

I just messed with the coolant control valve and it made it a lot better. my hot/cold dial is doing nothing. If only the truck ran hotter as a whole. It would make it perfect. But ill take this for now haha. Thanks everyone who helped out!

Axel-Breaker-Earl

Eric-Smedlund I just messed with the coolant control valve and it made it a lot better.

Told ya so!! 😉

Cusser

Guess what: pretty sure all that's available new for radiators is radiators for "automatics". I've run such radiator in my own '88 B2200 since 2011, and I get great, fast heat, most of us have 5-speeds, so have the "automatic" radiator.

Most of the "automatic" radiators these days are 1-row but have aluminum core so cool better than the factory brass/copper radiators, Mine never runs hot, Cab Plus, Arizona desert, highways, AC on most of year.

Red91EFI

Axel-Breaker-Earl

Process of elimination, start with the easy stuff first.