Engine Temp problem

[chuy22]

I am having a problem I have never had. My van at highway speeds tends to be running at aroung 212 f and at street speeds it is running at around 190-200. It just started doing this. Can this be a radiator cap problem? Or something else. I have a 2000 astro. Please help!!!!!!!!!!!!

[CD Smalley]

Could be a collaping lower radiator hose.

[chuy22]

Thanks, will try it out. Can I reuse the coolant or should I just go ahead and replale it. If I replace it will 1 bottle be enough?

[MT-2500]

Originally Posted by chuy22

Thanks, will try it out. Can I reuse the coolant or should I just go ahead and replale it. If I replace it will 1 bottle be enough?

Coolant need replaced ever so often.
Is it low on coolant or leaking anyplace?
First thing ckeck/replace thermostat and flush coolant system out.
Ckeck rad flow. And do not be to tight to by some new coolant for it.
MT

[chuy22]

Can you please explain how the collapsing lower radiator hose would affect the engine temperature. I still haven't had time to fix my van. I will try to get to it tomorrow.

[colinemckay]

> Can you please explain how the collapsing lower radiator hose would affect the engine temperature.

The lower rad hose connects to the input of the pump. If the hose is aged and weak, when the pump sucks fluid in, the hose may collapse, partially or fully, restricting flow of the coolant.

With the engine cool (and off) squeeze the lower hose, checking for soft spots along the entire length of the hose.

[old_master]

Originally Posted by colinemckay

> Can you please explain how the collapsing lower radiator hose would affect the engine temperature.

The lower rad hose connects to the input of the pump. If the hose is aged and weak, when the pump sucks fluid in, the hose may collapse, partially or fully, restricting flow of the coolant.

With the engine cool (and off) squeeze the lower hose, checking for soft spots along the entire length of the hose.

I agree, 100% correct! Good quality replacement lower radiator hoses have a spring inside them to totally eliminate the possibility of collapsing. Make sure your replacement has one. Look inside, if it has one, you'll see it.

[CD Smalley]

A+ to to those descriptions. I would add this is normally only a situation seen at highway speeds, higher RRMs. During city driving, at lower RPMs, the pump will be pulling less fluid and thus the hose will stay open enough to allow suffiecient cooling....

[chuy22]

Well I bought the quality hose and replaced it flushed out the system and topped it off. Still it is getting hot. I think I am just going to take it to a mecanic and have them fix it.

[Blue Bowtie]

212ºF is warm, but not excessive. Nonetheless, cooling at highway speeds should be adequate to maintian about the same temperatures as the 190-200ºF you are experiencing during other driving. More heat is being generated by the engine at highway speeds, but increased coolant and air flow should normally be adequate to remove that heat.

Other factors could be contributing to the heating;

1. Are you towing with the vehicle when experiencing the higher temperatures?
2. Are there any unusual exhaust noises? Exhaust restriction could contribute to overheating at higher engine speeds.
3. At highway speeds, if you shift the transmission to NEUTRAL and allow the vehicle to coast, does if lose road speed quickly, or coast freely? Driveline friction and rolling resistance can create extra load and result in overheating.
4. Coolant flow can be restricted by more than just a collapsed lower hose, although that is a commonly overlooked cause. Other causes are restricted or plugged internal radiator passages, slippage at or erosion of the water pump impeller, belt slippage limiting water pump effectiveness, sludge contamination of the cooling system within the engine restricting coolant flow, compression leaks into the cooling system, a thermostat which fails to open fully, contamination on the exterior of the radiator or air conditioner condenser (or even between the two) limiting air flow, and multiple other potential causes.
5. Excessive engine heat can be caused by carbon deposits in the combustion chambers, incorrect ignition timing, incorrect valve timing, inadequate lubrication, excessively lean fuel mixture, or low compression.
6. Excessive heat can be caused by the transmission if there is high torque converter slippage, air bubbles in the transmission oil, or slippage of friction surfaces.

I'm certain all possible causes are not listed here, but those are some that I have experienced.

[chuy22]

Now the van is getting hot while just waiting to reqach operation temp. I don't need to need to take it out for a drive. I suspect a bad water pump or thermostat. I checked the belt and it seems to be working fine. I thought it was the heater core, but I get heat out of the vents.

[chuy22]

OK, I just got my van back. Turns out I had a bad thermostat. Paid less than $100 including parts and labor. Now I can get back to driving my van in peace. I love it.

[smokinsiggy]

Originally Posted by chuy22

OK, I just got my van back. Turns out I had a bad thermostat. Paid less than $100 including parts and labor. Now I can get back to driving my van in peace. I love it.

have a 90 Astro AWD and changed my rad. yesterday (what a pain it was ) . now the old rad. was leaking at the top so the upper rad. hose to the thermostat never presurized before probably due to leaks . upon completion of the R&R Rad. , the reconditioned rad gets no pressurize upper hose either . complete pressure , no leaks , rad. circulates but the hose seems nothing passes through it to thermostat . would a stuck thermo. cause this problem ?

[MT-2500]

Originally Posted by smokinsiggy

have a 90 Astro AWD and changed my rad. yesterday (what a pain it was ) . now the old rad. was leaking at the top so the upper rad. hose to the thermostat never presurized before probably due to leaks . upon completion of the R&R Rad. , the reconditioned rad gets no pressurize upper hose either . complete pressure , no leaks , rad. circulates but the hose seems nothing passes through it to thermostat . would a stuck thermo. cause this problem ?

Could be.
But you need to start a new post with your problems.
Two diffrent problems on same post leds to two different confuzing answers.
MT