Won't warm up

[Gordon12]

So, my first Festiva. And first time with this problem in any car. So, I start her up. Let it warm up 5 to 10 minutes. I drive her all the way to work, about 25 minute drive on the highway. By the time I get to work, the temp gauge is just barely starting to warm up. The owner before me even stuck a chunk of cardboard in front of the small radiator. If the car just sits there with no flow, it will eventually get warm. Gauge will almost go half way, and than ibcan finally get some heat threw the vents. It's cold out rite now, but damn. Seems a bit excessive.

[bhearts]

So, my first Festiva. And first time with this problem in any car. So, I start her up. Let it warm up 5 to 10 minutes. I drive her all the way to work, about 25 minute drive on the highway. By the time I get to work, the temp gauge is just barely starting to warm up. The owner before me even stuck a chunk of cardboard in front of the small radiator. If the car just sits there with no flow, it will eventually get warm. Gauge will almost go half way, and than ibcan finally get some heat threw the vents. It's cold out rite now, but damn. Seems a bit excessive.

That's just how these cars are. Things that other members have tried that may work for you, a coolant flush - drain coolant, fill with water, run till warm, drain coolant, fill water, repeat. Until all your green/Brown colored coolant is no more. Now, with a full coolant system of water, add about a cup of powder cascade dishwasher detergent, unscented. Drive around for a while, make sure not to let engine sit over night with no anti freeze. Drain detergent, fill with water, drain , fill, drain fill until it looks clean, aka just water. Then drain and add fresh coolant back in. That dishwasher detergent cleans the scale buildup off the coolant passages and will allow better heat absorption into your coolant. Also could try putting a manual valve between thermostat and radiator. To totally shut off the flow too the radiator. Heater core cooling should suffice for a b3 in the dead of winter.

[TominMO]

Make sure you have a 190 degree or higher thermostat.
Close off the bumper and grill holes. Then use cardboard against the rad as a last resort. Consider using a bellypan to help keep cold air out of the engine bay, and the warm air in.
Flush out the heater core. (edit: See good advice in the above post.)
Make sure there is no obstruction to airflow going to the heater core; i.e. pull the duct going from the outside vent to the heater, and clean it out if needed.

[WmWatt]

Interior heat may be a separate problem. There's a permanent thread on the subject at the top of this repair forum page.

I plug in the block heater. I think all Festivas sold in Canada came with block heaters. Mine was factory installed. I try for 2hrs before starting but even 1/2hr helps.

[TominMO]

Oh I forgot, another thing you can do to keep heat in is to fill all the cavities with foam rubber or jute. There are cavities next to the rear seats, behind the rear wheel well arches, in the hatch, and in the doors. Even put in extra carpeting over the existing one. I think william wrote about what he put in the doors.

[Gordon12]

The guy I got it from, said heater core might be plugged, but when the engine actually warms up it seems to heat pretty good. Lol wow never heard of having to do all this just so the engine warms up. If it makes a difference my engine is actually the 1.8 out of a ford escort. Forgot to mention that.

[Festivahopeful]

What radiator is installed? I have an all aluminum racing radiator and have the same issue with my 1.8, it NEVER warms up until it is low on coolant (leaking water pump that is being fixed in my garage now) Also what someone else said about a good OEM thermostat. From what I read on your suspension post, I wish we lived closer in Oregon. You would think the same guy built both our cars lol. Mine is lowered on stiff as hell honda coilover sleeves as well with a cold running BP swap lol. I will let you know if I get my problems under control and how I did it.

[Gordon12]

Lol are you in oregon? Probably is the same guy, or a buddy of the same guy. I'll post a pick of radiator

[Gordon12]

See, just a lil guy.

[bhearts]

See, just a lil guy.

I'm all for blocking the upper radiator hose completely. I'd give that a try first
Or, a valve, and play with allowed flow rates

[TominMO]

I'm all for blocking the upper radiator hose completely. I'd give that a try first
Or, a valve, and play with allowed flow rates

Isn't that what the thermostat is for though? I'd try all the other stuff first. Install a new t-stat, unblock the heater core, see if that fixes it; if not, then there's a lot to be done with blocking the front vents, and also insulation.

[bhearts]

Isn't that what the thermostat is for though? I'd try all the other stuff first. Install a new t-stat, unblock the heater core, see if that fixes it; if not, then there's a lot to be done with blocking the front vents, and also insulation.

They are quite different devices

[Gordon12]

Well I'm currently flushed till mostly clear. Added the soad, let it warm up all the way till fan kicked on. Drove to autozone for the parts and some plugs. Flushing out the cascade soap now and changing my plugs. So we shall see.

[TominMO]

They are quite different devices

I guess I don't get what you are driving at. Completely blocking the upper rad hose means no flow at all, including thru the heater core. No coolant flow means the motor overheats. What did you have in mind?

A valve I understand; older MGs had a plumbing valve that you could completely shut off to keep coolant from going to (or maybe it was from) the heater core. But still--that's what the t-stat is for, if the idea is to regulate temp via flow rate. And none of these schemes will overcome the poor design of the heater core itself, i.e., too small. The design of the heater box may also be an issue, aside from the whole dash-vent situation.

[bhearts]

I guess I don't get what you are driving at. Completely blocking the upper rad hose means no flow at all, including thru the heater core. No coolant flow means the motor overheats. What did you have in mind?

A valve I understand; older MGs had a plumbing valve that you could completely shut off to keep coolant from going to (or maybe it was from) the heater core. But still--that's what the t-stat is for, if the idea is to regulate temp via flow rate. And none of these schemes will overcome the poor design of the heater core itself, i.e., too small. The design of the heater box may also be an issue, aside from the whole dash-vent situation.

The heater core gets fresh coolant regardless of the thermostat flow. That's why there's that little bypass nipple right before it that joins with the heater return coolant and goes back to the water pump. Blocking the flow too the rad guarantees that no ambient temperature coolant finds its way back into the engine. So the engine can actually hold temperature like it should